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{\b\fs32\par\pard\qc\li0\tx0\tx20000\~ SH\~(\~1\~)\~\~\~\~\~\~\~\~\~\~\~\~\~USER
COMMANDS\~\~\~\~\~\~\~\~\~\~\~\~SH\~(\~1\~)}
}{\brdrt\brdrsh\par}{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.NAME} NAME
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}sh, rsh \'2d shell,
the standard/restricted command and programming language {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.SYNOPSIS} SYNOPSIS
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}{\b sh }[ {\b\'b1 abcefhikmnoprstuvxCD
}] [ {\b\'2d R }file ] [ {\b\'b1 o }option
] .\~.\~. [ {\b\'2d }] [ arg .\~.\~. ] {\b\line rsh
}[ {\b\'b1 abcefhikmnoprstuvxCD }] [ {\b\'2d R
}file ] [ {\b\'b1 o }option ] .\~.\~. [ {\b\'2d
}] [ arg .\~.\~. ] {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.DESCRIPTION} DESCRIPTION
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}{\i Sh }is a command and
programming language that executes commands read from a terminal or a file.
{\i Rsh }is a restricted version of the standard command interpreter {\i sh};
it is used to set up login names and execution environments whose capabilities
are more controlled than those of the standard shell. See {\i Invocation
}below for the meaning of arguments to the shell. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Definitions} Definitions.
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}A {\i metacharacter }is
one of the following characters: {\b\par\pard\qc\li1120\tx1120\tx20000 ; & ( ) | < > new-line
space tab} \par\pard\qc\li840\tx840\tx20000 A {\i blank }is a {\b tab }or a {\b space}.
An {\i identifier }is a sequence of letters, digits, or underscores starting
with a letter or underscore. Identifiers are used as components of {\i variable
}names. A {\i vname }is a sequence of one or more identifiers separated
by a {\b{\fs26 .}} and optionally preceded by a {\b{\fs26 .}}.
Vnames are used as function and variable names. A {\i word }is a sequence
of {\i characters }from the character set defined by the current locale,
excluding non-quoted {\i metacharacters}. \par\pard\qc\li840\tx840\tx20000 A {\i command }is a sequence
of characters in the syntax of the shell language. The shell reads each
command and carries out the desired action either directly or by invoking
separate utilities. A built-in command is a command that is carried out
by the shell itself without creating a separate process. Some commands are
built-in purely for convenience and are not documented here. Built-ins that
cause side effects in the shell environment and built-ins that are found
before performing a path search (see {\uldb Execution}{\v HTML2RTF.Execution}{\*\comment{\i Execution }}below)
are documented here. For historical reasons, some of these built-ins behave
differently than other built-ins and are called {\i special built-ins}.
{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Commands} Commands. \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}A
{\i simple-command }is a list of variable assignments (see {\uldb Variable Assignments}{\v HTML2RTF.Variable.Assignments}{\*\comment{\i Variable
Assignments }}below) or a sequence of {\i blank }separated words which
may be preceded by a list of variable assignments (see {\uldb Environment}{\v HTML2RTF.Environment}{\*\comment{\i Environment
}}below). The first word specifies the name of the command to be executed.
Except as specified below, the remaining words are passed as arguments to
the invoked command. The command name is passed as argument 0 (see {\i exec}(2)).
The {\i value }of a simple-command is its exit status; 0-255 if it terminates
normally; 256+{\i signum\~}if it terminates abnormally (the name of
the signal corresponding to the exit status can be obtained via the {\b\'2d l
}option of the {\b kill }built-in utility). \par\pard\qc\li840\tx840\tx20000 A {\i pipeline
}is a sequence of one or more {\i commands }separated by {\b |}.
The standard output of each command but the last is connected by a {\i pipe}(2)
to the standard input of the next command. Each command, except possibly
the last, is run as a separate process; the shell waits for the last command
to terminate. The exit status of a pipeline is the exit status of the last
command. Each pipeline can be preceded by the {\i reserved word }{\b !
}which causes the exit status of the pipeline to become 0 if the exit
status of the last command is non-zero, and 1 if the exit status of the
last command is 0. \par\pard\qc\li840\tx840\tx20000 A {\i list }is a sequence of one or more pipelines
separated by {\b ;}, {\b&}, {\b |&}, {\b&&},
or {\b |\~|}, and optionally terminated by {\b ;},
{\b&}, or {\b |&}. Of these five symbols, {\b ;},
{\b&}, and {\b |& }have equal precedence, which
is lower than that of {\b&& }and {\b |\~|}.
The symbols {\b&& }and {\b |\~| }also have equal
precedence. A semicolon ({\b ;}) causes sequential execution of
the preceding pipeline; an ampersand ({\b&}) causes asynchronous
execution of the preceding pipeline (i.e., the shell does {\i not }wait
for that pipeline to finish). The symbol {\b |& }causes asynchronous
execution of the preceding pipeline with a two-way pipe established to the
parent shell; the standard input and output of the spawned pipeline can
be written to and read from by the parent shell by applying the redirection
operators {\b<& }and {\b>& }with arg {\b p
}to commands and by using {\b\'2d p }option of the built-in
commands {\b read }and {\b print }described later. The
symbol {\b&& }(\~{\b |\~|}\~) causes
the {\i list }following it to be executed only if the preceding pipeline
returns a zero (non-zero) value. One or more new-lines may appear in a {\i list
}instead of a semicolon, to delimit a command. \par\pard\qc\li840\tx840\tx20000 A {\i command }is either
a simple-command or one of the following. Unless otherwise stated, the value
returned by a command is that of the last simple-command executed in the
command. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 for} {\i vname\~}[\~{\b in}
{\i word\~}.\~.\~. \~] {\b ;do}{\i list\~}{\b ;done}
\tab Each time a {\b for }command is executed, {\i vname }is set
to the next {\i word }taken from the {\b in }{\i word }list.
If {\b in}{\i word\~}.\~.\~. is omitted, then the
{\b for }command executes the {\b do} {\i list\~}once
for each positional parameter that is set starting from {\b 1 }(see
{\uldb Parameter Expansion}{\v HTML2RTF.Parameter.Expansion}{\*\comment{\i Parameter Expansion }}below). Execution ends
when there are no more words in the list. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 for ((} [\~{\i expr1\~}\~]
{\b ;} [\~{\i expr2\~}\~] {\b ;} [\~{\i expr3\~}\~]
{\b ))}{\b ;do}{\i list\~}{\b ;done} \tab The
arithmetic expression {\i expr1 }is evaluated first (see {\uldb Arithmetic Evaluation}{\v HTML2RTF.Arithmetic.Evaluation}{\*\comment{\i Arithmetic
Evaluation }}below). The arithmetic expression {\i expr2 }is repeatedly
evaluated until it evaluates to zero and when non-zero, {\i list }is executed
and the arithmetic expression {\i expr3 }evaluated. If any expression is
omitted, then it behaves as if it evaluated to 1. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 select}
{\i vname\~}[\~{\b in} {\i word\~}.\~.\~.
\~] {\b ;do}{\i list\~}{\b ;done} \tab A {\b select
}command prints on standard error (file descriptor 2) the set of {\i word}s,
each preceded by a number. If {\b in}{\i word\~}.\~.\~.
is omitted, then the positional parameters starting from {\b 1 }are
used instead (see {\uldb Parameter Expansion}{\v HTML2RTF.Parameter.Expansion}{\*\comment{\i Parameter Expansion }}below).
The {\fs22{\b PS3 }}prompt is printed and a line is read
from the standard input. If this line consists of the number of one of the
listed {\i word}s, then the value of the variable {\i vname }is set to
the {\i word }corresponding to this number. If this line is empty, the
selection list is printed again. Otherwise the value of the variable {\i vname
}is set to {\i null}. The contents of the line read from standard input
is saved in the variable {\fs22{\b REPLY}. }The {\i list
}is executed for each selection until a {\b break }or {\i end-of-file
}is encountered. If the {\fs22{\b REPLY }}variable is
set to {\i null }by the execution of {\i list}, then the selection list
is printed before displaying the {\fs22{\b PS3 }}prompt
for the next selection. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 case} {\i word\~}{\b in}
[\~[\~{\b (}\~]{\i pattern\~}[\~| {\i pattern\~}\~].\~.\~.{\b )}{\i list\~}{\b ;;}\~].\~.\~.{\b esac}
\tab A {\b case }command executes the {\i list }associated with
the first {\i pattern }that matches {\i word}. The form of the patterns
is the same as that used for file-name generation (see {\uldb File Name Generation}{\v HTML2RTF.File.Name.Generation}{\*\comment{\i File
Name Generation }}below). The {\b ;; }operator causes execution
of {\b case }to terminate. If {\b ;& }is used in place
of {\b ;; }the next subsequent list, if any, is executed. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 if}
{\i list\~}{\b ;then} {\i list\~}[\~{\b elif}
{\i list\~}{\b ;then}{\i list\~}\~].\~.\~.[\~{\b ;else}{\i list\~}\~]{\b ;fi}
\tab The {\i list }following {\b if} is executed and, if it returns
a zero exit status, the {\i list }following the first {\b then }is
executed. Otherwise, the {\i list }following {\b elif} is executed
and, if its value is zero, the {\i list }following the next {\b then
}is executed. Failing each successive {\b elif }{\i list\~},
the {\b else }{\i list }is executed. If the {\b if }{\i list
}has non-zero exit status and there is no {\b else }{\i list},
then the {\b if }command returns a zero exit status. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 while}
{\i list\~}{\b ;do} {\i list\~}{\b ;done} \tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 until}
{\i list\~}{\b ;do} {\i list\~}{\b ;done} \tab A
{\b while }command repeatedly executes the {\b while }{\i list
}and, if the exit status of the last command in the list is zero, executes
the {\b do }{\i list}; otherwise the loop terminates. If no commands
in the {\b do }{\i list }are executed, then the {\b while }command
returns a zero exit status; {\b until }may be used in place of
{\b while }to negate the loop termination test. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 ((}{\i expression\~}{\b ))}
\tab The {\i expression }is evaluated using the rules for arithmetic evaluation
described below. If the value of the arithmetic expression is non-zero,
the exit status is 0, otherwise the exit status is 1. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 (}{\i list\~}{\b )}
\tab Execute {\i list }in a separate environment. Note, that if two adjacent
open parentheses are needed for nesting, a space must be inserted to avoid
evaluation as an arithmetic command as described above. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\{ }{\i list\~}{\b ;\}}
\tab{\i list }is simply executed. Note that unlike the metacharacters {\b (
}and {\b )}, {\b\{ }and {\b\} }are {\i reserved
word}s and must occur at the beginning of a line or after a {\b ; }in
order to be recognized. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 [[}{\i expression \~}{\b ]]}
\tab Evaluates {\i expression }and returns a zero exit status when {\i expression
}is true. See {\i Conditional Expressions }below, for a description of
{\i expression}. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 function} {\i varname\~}{\b\{}
{\i list\~}{\b ;\}} \tab{\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 varname\~}{\b () \{}
{\i list\~}{\b ;\}} \tab Define a function which is referenced
by {\i varname}. A function whose {\i varname }contains a {\b{\fs26 .}
}is called a discipline function and the portion of the {\i varname
}preceding the last {\b{\fs26 .} }must refer to an existing
variable. The body of the function is the {\i list }of commands between
{\b\{ }and {\b\}}. A function defined with the {\b function}
{\i varname\~}syntax can also be used as an argument to the {\b .}
special built-in command to get the equivalent behavior as if the {\i varname\~}{\b ()}
syntax were used to define it. (See {\i Functions }below.) {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 time}
[\~{\i pipeline\~}\~] \tab If {\i pipeline\~}is omitted
the user and system time for the current shell and completed child processes
is printed on standard error. Otherwise, {\i pipeline }is executed and
the elapsed time as well as the user and system time are printed on standard
error. \par\pard\qc\li840\tx840\tx20000 The following reserved words are recognized as reserved only
when they are the first word of a command and are not quoted: {\b\par\pard\qc\li1120\tx1120\tx20000 if
then else elif fi case esac for while until do done \{ \} function select
time [[ ]] ! }{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Variable.Assignments} Variable
\~Assignments. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}One or more
variable assignments can start a simple command or can be arguments to the
{\b typeset}, {\b export}, or {\b readonly }special
built-in commands. The syntax for an {\i assignment\~}is of the form:
{\i\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 varname\~}{\b =}{\i word\~}\tab{\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 varname\~}{\b [}{\i word\~}{\b ]}={\b}{\i word\~}{\b\tab}No
space is permitted between {\i varname\~}and the {\b =} or
between {\b =} and {\i word\~}. {\i\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 varname\~}{\b =(}{\i assign_list\~}{\b )}
\tab No space is permitted between {\i varname\~}and the {\b =}.
An {\i assign_list\~}can be one of the following: {\i\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 word\~}...
\tab Indexed array assignment. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 [}{\i word\~}{\b ]=}{\i word\~}.\~.\~.
\tab Associative array assignment. {\i\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 assignment\~}.\~.\~.
\tab Nested variable assignment. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 typeset} [\~{\i options}\~]
{\i assignment\~}.\~.\~. \tab Nested variable assignment. Multiple
assignments can be specified by separating each of them with a {\b ;}.
{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Comments} Comments. \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}A
word beginning with {\b # }causes that word and all the following
characters up to a new-line to be ignored. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Aliasing} Aliasing.
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}The first word of each
command is replaced by the text of an {\b alias }if an {\b alias
}for this word has been defined. An {\b alias }name consists
of any number of characters excluding metacharacters, quoting characters,
file expansion characters, parameter expansion and command substitution
characters, and {\b =}. The replacement string can contain any
valid shell script including the metacharacters listed above. The first
word of each command in the replaced text, other than any that are in the
process of being replaced, will be tested for aliases. If the last character
of the alias value is a {\i blank }then the word following the alias will
also be checked for alias substitution. Aliases can be used to redefine
built-in commands but cannot be used to redefine the reserved words listed
above. Aliases can be created and listed with the {\b alias }command
and can be removed with the {\b unalias }command. {\i\par\pard\qc\li840\tx840\tx20000 Aliasing
}is performed when scripts are read, not while they are executed. Therefore,
for an alias to take effect, the {\b alias }definition command
has to be executed before the command which references the alias is read.
\par\pard\qc\li840\tx840\tx20000 The following aliases are compiled into the shell but can be unset or
redefined: {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 autoload='typeset \'2dfu' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 command='command
' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 fc=hist }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 float='typeset \'2dE'
}\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 functions='typeset \'2df' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 hash='alias
\'2dt \'2d\~\'2d' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 history='hist \'2dl'
}\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 integer='typeset \'2di' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 nameref='typeset
\'2dn' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 nohup='nohup ' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 r='hist \'2ds'
}\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 redirect='command exec' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 stop='kill \'2ds
{\fs22 STOP}' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 suspend='kill \'2ds {\fs22 STOP}
$$' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 times='\{ \{ time;\} 2>&1;\}' }\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 type='whence
\'2dv' }\tab{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Tilde.Substitution} Tilde
\~Substitution. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}After alias
substitution is performed, each word is checked to see if it begins with
an unquoted {\b ~}. For tilde substitution, {\i word }also refers
to the {\i word }portion of parameter expansion (see {\uldb Parameter Expansion}{\v HTML2RTF.Parameter.Expansion}{\*\comment{\i Parameter
Expansion }}below). If it does, then the word up to a {\b / }is
checked to see if it matches a user name in the password database (often
the {\b /etc/passwd }file). If a match is found, the {\b ~ }and
the matched login name are replaced by the login directory of the matched
user. If no match is found, the original text is left unchanged. A {\b ~
}by itself, or in front of a {\b /}, is replaced by {\fs22{\b $HOME}.
}A {\b ~ }followed by a {\b + }or {\b\'2d }is
replaced by the value of {\b{\fs22 $PWD }}and {\b{\fs22 $OLDPWD
}}respectively. \par\pard\qc\li840\tx840\tx20000 In addition, when expanding a {\i variable assignment},
{\i tilde }substitution is attempted when the value of the assignment begins
with a {\b ~}, and when a {\b ~ }appears after a {\b :}.
The {\b : }also terminates a {\b ~ }login name. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Command.Substitution} Command
\~Substitution. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}The standard
output from a command enclosed in parentheses preceded by a dollar sign
( {\b $(\~) }) or a pair of grave accents (\~{\b{\fs26 `}\~{\fs26 `}}\~)
may be used as part or all of a word; trailing new-lines are removed. In
the second (obsolete) form, the string between the quotes is processed for
special quoting characters before the command is executed (see {\uldb Quoting}{\v HTML2RTF.Quoting}{\*\comment{\i Quoting
}}below). The command substitution \~{\b $(\~cat file\~)}\~can
be replaced by the equivalent but faster \~{\b $(\~<file\~)}\~.
{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Arithmetic.Substitution} Arithmetic \~Substitution.
\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}An arithmetic expression enclosed
in double parentheses preceded by a dollar sign ( {\b $((\~)) })
is replaced by the value of the arithmetic expression within the double
parentheses. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Process.Substitution} Process \~Substitution.
\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}This feature is only available
on versions of the UNIX operating system that support the {\b /dev/fd
}directory for naming open files. Each command argument of the form
{\b< (}{\i list\~}{\b )} or {\b> (}{\i list\~}{\b )}
will run process {\i list }asynchronously connected to some file in {\b /dev/fd}.
The name of this file will become the argument to the command. If the form
with {\b> }is selected then writing on this file will provide
input for {\i list}. If {\b< }is used, then the file passed
as an argument will contain the output of the {\i list }process. For example,
{\b\par\pard\qc\li1120\tx1120\tx20000 paste <(cut \'2df1} {\i file1}{\b ) <(cut
\'2df3} {\i file2}{\b ) | tee >(}{\i process1}{\b )
>(}{\i process2}{\b )}{\i }{\i\par\pard\qc\li1120\tx1120\tx20000 cuts }fields 1 and
3 from the files {\i file1 }and {\i file2 }respectively, {\i pastes }the
results together, and sends it to the processes {\i process1 }and {\i process2},
as well as putting it onto the standard output. Note that the file, which
is passed as an argument to the command, is a UNIX {\i pipe}(2) so programs
that expect to {\i lseek}(2) on the file will not work. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Parameter.Expansion} Parameter
\~Expansion. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}A {\i parameter
}is a {\i variable}, one or more digits, or any of the characters {\b *},
{\b @}, {\b #}, {\b ?}, {\b\'2d},
{\b $}, and {\b !\~}. A {\i variable }is denoted
by a {\i vname}. To create a variable whose {\i vname }contains a {\b{\fs26 .}},
a variable whose {\i vname }consists of everything before the last {\b{\fs26 .}}
must already exist. A {\i variable }has a {\i value }and zero or more
{\i attributes}. {\i Variables }can be assigned {\i values }and {\i attributes
}by using the {\b typeset }special built-in command. The attributes
supported by the shell are described later with the {\b typeset }special
built-in command. Exported variables pass values and attributes to the environment.
\par\pard\qc\li840\tx840\tx20000 The shell supports both indexed and associative arrays. An element of
an array variable is referenced by a {\i subscript}. A {\i subscript }for
an indexed array is denoted by an {\i arithmetic expression }(see {\uldb Arithmetic Evaluation}{\v HTML2RTF.Arithmetic.Evaluation}{\*\comment{\i Arithmetic
Evaluation }}below) between a {\b [ }and a {\b ]}.
To assign values to an indexed array, use {\b set \'2dA} {\i vname}
{\i value} .\~.\~. . The value of all subscripts must be in the
range of 0 through 4095. Indexed arrays need not be declared. Any reference
to a variable with a valid subscript is legal and an array will be created
if necessary. \par\pard\qc\li840\tx840\tx20000 An associative array is created with the {\b\'2d A
}option to {\b typeset. }A {\i subscript }for an associative
array is denoted by a string enclosed between {\b [ }and {\b ]}.
\par\pard\qc\li840\tx840\tx20000 Referencing any array without a subscript is equivalent to referencing
the array with subscript 0. \par\pard\qc\li840\tx840\tx20000 The {\i value }of a {\i variable }may be
assigned by writing: {\i\par\pard\qc\li1120\tx1120\tx20000 vname}{\b =}{\i value\~\~}[\~{\i vname}{\b =}{\i value
}\~] .\~.\~. \par\pard\qc\li840\tx840\tx20000 or {\i\line vname}{\b [}{\i subscript}{\b ]=}{\i value\~\~}[\~{\i vname}{\b [}{\i subscript}{\b ]=}{\i value
}\~] .\~.\~. \par\pard\qc\li840\tx840\tx20000 Note that no space is allowed before or
after the {\b =}. \par\pard\qc\li840\tx840\tx20000 A {\i nameref }is a variable that is a reference
to another variable. A nameref is created with the {\b\'2d n }attribute
of {\b typeset}. The value of the variable at the time of the {\b typeset
}command becomes the variable that will be referenced whenever the
nameref variable is used. The name of a nameref cannot contain a {\b{\fs26 .}}.
When a variable or function name contains a {\b{\fs26 .}},
and the portion of the name up to the first {\b{\fs26 .}}
matches the name of a nameref, the variable referred to is obtained by replacing
the nameref portion with the name of the variable referenced by the nameref.
A nameref provides a convenient way to refer to the variable inside a function
whose name is passed as an argument to a function. For example, if the name
of a variable is passed as the first argument to a function, the command
{\b\line typeset \'2dn var=$1} \line inside the function
causes references and assignments to {\b var }to be references
and assignments to the variable whose name has been passed to the function.
\par\pard\qc\li840\tx840\tx20000 If either of the floating point attributes, {\b\'2d E}, or
{\b\'2d F}, or the integer attribute, {\b\'2d i},
is set for {\i vname}, then the {\i value }is subject to arithmetic evaluation
as described below. \par\pard\qc\li840\tx840\tx20000 Positional parameters, parameters denoted by a number,
may be assigned values with the {\b set }special built-in command.
Parameter {\b $0 }is set from argument zero when the shell is invoked.
\par\pard\qc\li840\tx840\tx20000 The character {\b $ }is used to introduce substitutable {\i parameters}.
{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b\}} \tab The
shell reads all the characters from {\b $\{ }to the matching {\b\}
}as part of the same word even if it contains braces or metacharacters.
The value, if any, of the parameter is substituted. The braces are required
when {\i parameter }is followed by a letter, digit, or underscore that
is not to be interpreted as part of its name, when the variable name contains
a {\b{\fs26 .}}, or when a variable is subscripted. If
{\i parameter }is one or more digits then it is a positional parameter.
A positional parameter of more than one digit must be enclosed in braces.
If {\i parameter }is {\b * }or {\b @}, then all the positional
parameters, starting with {\b $1}, are substituted (separated by
a field separator character). If an array {\i vname }with subscript {\b *
}or {\b @ }is used, then the value for each of the elements
is substituted, separated by the first character of the value of {\fs22{\b IFS}.
}{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{#}{\i parameter\~}{\b\}} \tab If {\i parameter
}is {\b * }or {\b @}, the number of positional parameters
is substituted. Otherwise, the length of the value of the {\i parameter }is
substituted. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{#}{\i vname}{\b [*]\}} \tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{#}{\i vname}{\b [@]\}}
\tab The number of elements in the array {\i vname }is substituted. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{!}{\i vname\~}{\b\}}
\tab Expands to the name of the variable referred to by {\i vname}. This
will be {\i vname }except when {\i vname }is a name reference. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{!}{\i vname\~}{\b [}{\i subscript\~}{\b ]\}}{\i
\tab}Expands to name of the subscript unless {\i subscript }is {\b *
}or {\b @}. When {\i subscript }is {\b *}, the
list of array subscripts for {\i vname\~}is generated. For a variable
that is not an array, the value is 0 if the variable is set. Otherwise it
is null. When {\i subscript }is {\b @}, same as above, except
that when used in double quotes, each array subscript yields a separate
argument. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{!}{\i prefix\~}{\b *\}} \tab Expands
to the names of the variables whose names begin with {\i prefix}. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b :\'2d}{\i word\~}{\b\}}
\tab If {\i parameter }is set and is non-null then substitute its value;
otherwise substitute {\i word}. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b :=}{\i word\~}{\b\}}
\tab If {\i parameter }is not set or is null then set it to {\i word}; the
value of the parameter is then substituted. Positional parameters may not
be assigned to in this way. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b :?}{\i word\~}{\b\}}
\tab If {\i parameter }is set and is non-null then substitute its value;
otherwise, print {\i word }and exit from the shell (if not interactive).
If {\i word }is omitted then a standard message is printed. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b :+}{\i word\~}{\b\}}
\tab If {\i parameter }is set and is non-null then substitute {\i word};
otherwise substitute nothing. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b :}{\i offset\~}{\b :}{\i length\~}{\b\}}
\tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b :}{\i offset\~}{\b\}}
\tab Expands to the portion of the value of {\i parameter }starting at the
character (counting from {\b 0\~}) determined by expanding
{\i offset }as an arithmetic expression and consisting of the number of
characters determined by the arithmetic expression defined by {\i length.
}In the second form, the remainder of the value is used. If {\i parameter
}is {\b * }or {\b @}, or is an array name indexed by
{\b * }or {\b @}, then {\i offset }and {\i length }refer
to the array index and number of elements respectively. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b #}{\i pattern\~}{\b\}}
\tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b ##}{\i pattern\~}{\b\}}
\tab If the shell {\i pattern }matches the beginning of the value of {\i parameter},
then the value of this expansion is the value of the {\i parameter }with
the matched portion deleted; otherwise the value of this {\i parameter }is
substituted. In the first form the smallest matching pattern is deleted
and in the second form the largest matching pattern is deleted. When {\i parameter
}is {\b @}, {\b *}, or an array variable with subscript
{\b @ }or {\b *}, the substring operation is applied to
each element in turn. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b %}{\i pattern\~}{\b\}}
\tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b %%}{\i pattern\~}{\b\}}
\tab If the shell {\i pattern }matches the end of the value of {\i parameter},
then the value of this expansion is the value of the {\i parameter }with
the matched part deleted; otherwise substitute the value of {\i parameter}.
In the first form the smallest matching pattern is deleted and in the second
form the largest matching pattern is deleted. When {\i parameter }is {\b @},
{\b *}, or an array variable with subscript {\b @ }or
{\b *}, the substring operation is applied to each element in turn.
{\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b /}{\i pattern\~}{\b /}{\i string\~}{\b\}
}\tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b //}{\i pattern\~}{\b /}{\i string\~}{\b\}
\tab}{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b /#}{\i pattern\~}{\b /}{\i string\~}{\b\}
\tab}{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 $\{}{\i parameter\~}{\b /%}{\i pattern\~}{\b /}{\i string\~}{\b\}
\tab}Expands {\i parameter }and replaces the longest match of {\i pattern
}with the given {\i string. }Each occurrence of {\b\'5c}{\i n\~}in
{\i string }is replaced by the portion of {\i parameter\~}that matches
the {\i n\~}-th sub-pattern. In the first form, only the first occurrence
of {\i pattern }is replaced. In the second form, each match for {\i pattern
}is replaced by the given {\i string. }The third form restricts the pattern
match to the beginning of the string while the fourth form restricts the
pattern match to the end of the string. When {\i string }is null, the {\i pattern
}will be deleted and the {\b / }in front of {\i string }may
be omitted. When {\i parameter }is {\b @}, {\b *}, or
an array variable with subscript {\b @ }or {\b *}, the
substitution operation is applied to each element in turn. \par\pard\qc\li840\tx840\tx20000 In the above,
{\i word }is not evaluated unless it is to be used as the substituted string,
so that, in the following example, {\b pwd }is executed only if
{\b d }is not set or is null: \par\pard\qc\li1120\tx1120\tx20000 print \~$\{d:\'2d\~$(\~pwd\~)\~\}
\par\pard\qc\li840\tx840\tx20000 If the colon ( {\b : ) }is omitted from the above expressions,
then the shell only checks whether {\i parameter }is set or not. \par\pard\qc\li840\tx840\tx20000 The
following parameters are automatically set by the shell: {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 #
}\tab The number of positional parameters in decimal. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d
}\tab Options supplied to the shell on invocation or by the {\b set
}command. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 ? }\tab The decimal value returned by the last
executed command. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 $ }\tab The process number of this shell.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 _ }\tab Initially, the value of {\b _ }is an absolute
pathname of the shell or script being executed as passed in the {\i environment}.
Subsequently it is assigned the last argument of the previous command. This
parameter is not set for commands which are asynchronous. This parameter
is also used to hold the name of the matching {\b{\fs22 MAIL }}file
when checking for mail. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 ! }\tab The process number of the last
background command invoked. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 .sh.edchar }\tab This variable
contains the value of the keyboard character (or sequence of characters
if the first character is an ESC, ascii {\b 033\~}) that has
been entered when processing a {\b{\fs22 KEYBD }}trap (see
{\uldb Key Bindings}{\v HTML2RTF.Key.Bindings}{\*\comment{\i Key Bindings }}below). If the value is changed as
part of the trap action, then the new value replaces the key (or key sequence)
that caused the trap. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 .sh.edcol }\tab The character position
of the cursor at the time of the most recent {\b{\fs22 KEYBD }}trap.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 .sh.edmode }\tab The value is set to ESC when processing a
{\b{\fs22 KEYBD }}trap while in {\b vi }insert
mode. (See {\i Vi Editing Mode }below.) Otherwise, {\b .sh.edmode }is
null when processing a {\b{\fs22 KEYBD }}trap. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 .sh.edtext
}\tab The characters in the input buffer at the time of the most recent
{\b{\fs22 KEYBD }}trap. The value is null when not processing
a {\b{\fs22 KEYBD }}trap. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 .sh.name }\tab Set
to the name of the variable at the time that a discipline function is invoked.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 .sh.subscript }\tab Set to the name subscript of the variable
at the time that a discipline function is invoked. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 .sh.value }\tab Set
to the value of the variable at the time that the {\b set }discipline
function is invoked. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 .sh.version }\tab Set to a value that
identifies the version of this shell. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 LINENO }}\tab The
current line number within the script or function being executed. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 OLDPWD
}}\tab The previous working directory set by the {\b cd }command.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 OPTARG }}\tab The value of the last option argument
processed by the {\b getopts }built-in command. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 OPTIND
}}\tab The index of the last option argument processed by the {\b getopts
}built-in command. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 PPID }}\tab The process
number of the parent of the shell. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 PWD }}\tab The
present working directory set by the {\b cd }command. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 RANDOM
}}\tab Each time this variable is referenced, a random integer,
uniformly distributed between 0 and 32767, is generated. The sequence of
random numbers can be initialized by assigning a numeric value to {\fs22{\b RANDOM}.
}{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 REPLY }}\tab This variable is set by the
{\b select }statement and by the {\b read }built-in command
when no arguments are supplied. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 SECONDS }}\tab Each
time this variable is referenced, the number of seconds since shell invocation
is returned. If this variable is assigned a value, then the value returned
upon reference will be the value that was assigned plus the number of seconds
since the assignment. \par\pard\qc\li840\tx840\tx20000 The following variables are used by the shell:
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 CDPATH }}\tab The search path
for the {\b cd }command. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 COLUMNS }}\tab If
this variable is set, the value is used to define the width of the edit
window for the shell edit modes and for printing {\b select }lists.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 EDITOR }}\tab If the value of this variable ends
in {\i emacs}, {\i gmacs}, or {\i vi }and the {\b{\fs22 VISUAL
}}variable is not set, then the corresponding option (see special
built-in command {\uldb set}{\v HTML2RTF.set}{\*\comment{\b set }}below) will be turned on.
\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b ENV }\tab}If this variable is set, then parameter
expansion, command substitution, and arithmetic substitution are performed
on the value to generate the pathname of the script that will be executed
when the shell is invoked (see {\uldb Invocation}{\v HTML2RTF.Invocation}{\*\comment{\i Invocation }}below).
This file is typically used for {\b alias }and {\b function
}definitions. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 FCEDIT }}\tab Obsolete name
for the default editor name for the {\b hist }command. {\b{\fs22 FCEDIT
}}is not used when {\b{\fs22 HISTEDIT }}is set.
\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b FIGNORE }\tab}A pattern that defines the set
of filenames that will be ignored when performing filename matching. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b FPATH
}\tab}The search path for function definitions. This path is searched
for a file with the same name as the function or command when a function
with the {\b\'2d u }attribute is referenced and when a command
is not found. If an executable file with the name of that command is found,
then it is read and executed in the current environment. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 HISTCMD
}}\tab Number of the current command in the history file. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 HISTEDIT
}}\tab Name for the default editor name for the {\b hist }command.
\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b HISTFILE }\tab}If this variable is set when the
shell is invoked, then the value is the pathname of the file that will be
used to store the command history (see {\uldb Command Re-entry}{\v HTML2RTF.Command.Re.entry}{\*\comment{\i Command
Re-entry }}below). \par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b HISTSIZE }\tab}If this
variable is set when the shell is invoked, then the number of previously
entered commands that are accessible by this shell will be greater than
or equal to this number. The default is 128. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 HOME }}\tab The
default argument (home directory) for the {\b cd }command. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b IFS
}\tab}Internal field separators, normally {\b space}, {\b tab},
and {\b new-line }that are used to separate the results of command
substitution or parameter expansion and to separate fields with the built-in
command {\b read}. The first character of the {\fs22{\b IFS
}}variable is used to separate arguments for the {\b "$*" }substitution
(see {\uldb Quoting}{\v HTML2RTF.Quoting}{\*\comment{\i Quoting }}below). Each single occurrence of an {\fs22{\b IFS
}}character in the string to be split, that is not in the {\i isspace\~}character
class, and any adjacent characters in {\fs22{\b IFS }}that
are in the {\i isspace\~}character class, delimit a field. One or more
characters in {\fs22{\b IFS }}that belong to the {\i isspace\~}character
class, delimit a field. In addition, if the same {\i isspace\~}character
appears consecutively inside {\fs22{\b IFS}, }this character
is treated as if it were not in the {\i isspace\~}class, so that if
{\fs22{\b IFS }}consists of two {\b tab }characters,
then two adjacent {\b tab }characters delimit a null field. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 LANG
}}\tab This variable determines the locale category for any category
not specifically selected with a variable starting with {\b{\fs22 LC_
}}or {\fs22{\b LANG}. }{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 LC_ALL
}}\tab This variable overrides the value of the {\b{\fs22 LANG
}}variable and any other {\b{\fs22 LC_ }}variable.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 LC_COLLATE }}\tab This variable determines the
locale category for character collation information. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 LC_CTYPE
}}\tab This variable determines the locale category for character
handling functions. It determines the character classes for pattern matching
(see {\uldb File Name Generation}{\v HTML2RTF.File.Name.Generation}{\*\comment{\i File Name Generation }}below). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 LC_NUMERIC
}}\tab This variable determines the locale category for the decimal
point character. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 LINES }}\tab If this variable
is set, the value is used to determine the column length for printing {\b select
}lists. Select lists will print vertically until about two-thirds
of {\b{\fs22 LINES }}lines are filled. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 MAIL
}}\tab If this variable is set to the name of a mail file {\i and
}the {\b{\fs22 MAILPATH }}variable is not set, then the
shell informs the user of arrival of mail in the specified file. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 MAILCHECK
}}\tab This variable specifies how often (in seconds) the shell
will check for changes in the modification time of any of the files specified
by the {\b{\fs22 MAILPATH }}or {\b{\fs22 MAIL }}variables.
The default value is 600 seconds. When the time has elapsed the shell will
check before issuing the next prompt. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 MAILPATH }}\tab A
colon ( {\b : }) separated list of file names. If this variable
is set, then the shell informs the user of any modifications to the specified
files that have occurred within the last {\b{\fs22 MAILCHECK }}seconds.
Each file name can be followed by a {\b ? }and a message that will
be printed. The message will undergo parameter expansion, command substitution,
and arithmetic substitution with the variable {\b $_ }defined as
the name of the file that has changed. The default message is {\i you have
mail in $_\~. }{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 PATH }}\tab The search path
for commands (see {\uldb Execution}{\v HTML2RTF.Execution}{\*\comment{\i Execution }}below). The user may
not change {\b{\fs22 PATH} }if executing under {\b rsh
}(except in {\b .profile\~). }\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b PS1
}\tab}The value of this variable is expanded for parameter expansion,
command substitution, and arithmetic substitution to define the primary
prompt string which by default is ``{\b $\~\~\~}''.
The character {\b ! }in the primary prompt string is replaced by
the {\i command }number (see {\uldb Command Re-entry}{\v HTML2RTF.Command.Re.entry}{\*\comment{\i Command Re-entry
}}below). Two successive occurrences of {\b ! }will produce
a single {\b ! }when the prompt string is printed. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b PS2
}\tab}Secondary prompt string, by default ``{\b> \~}''.
\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b PS3 }\tab}Selection prompt string used within
a {\b select }loop, by default ``{\b #? \~}''. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b PS4
}\tab}The value of this variable is expanded for parameter evaluation,
command substitution, and arithmetic substitution and precedes each line
of an execution trace. By default, {\fs22{\b PS4 }}is ``{\b +
\~}''. In addition when {\fs22{\b PS4 }}is unset,
the execution trace prompt is also ``{\b + \~}''. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22{\b SHELL
}\tab}The pathname of the {\i shell }is kept in the environment.
At invocation, if the basename of this variable is {\b rsh}, {\b rksh},
or {\b krsh}, then the shell becomes restricted. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 TMOUT
}}\tab If set to a value greater than zero, {\b{\fs22 TMOUT
}}will be the default timeout value for the {\b read }built-in
command. The {\b select }compound command terminates after {\b{\fs22 TMOUT
}}seconds when input is from a terminal. Otherwise, the shell
will terminate if a line is not entered within the prescribed number of
seconds while reading from a terminal. (Note that the shell can be compiled
with a maximum bound for this value which cannot be exceeded.) {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000{\fs22 VISUAL
}}\tab If the value of this variable ends in {\i emacs}, {\i gmacs},
or {\i vi }then the corresponding option (see Special Command {\uldb set}{\v HTML2RTF.set}{\*\comment{\b set
}}below) will be turned on. The value of {\b{\fs22 VISUAL
}}overrides the value of {\b{\fs22 EDITOR. }}\par\pard\qc\li840\tx840\tx20000 The
shell gives default values to {\b{\fs22 PATH}}, {\b{\fs22 PS1}},
{\b{\fs22 PS2}}, {\b{\fs22 PS3}}, {\b{\fs22 PS4}},
{\b{\fs22 MAILCHECK}}, {\b{\fs22 FCEDIT}},
{\b{\fs22 TMOUT}} and {\b{\fs22 IFS}},
while {\fs22{\b HOME}, }{\fs22{\b SHELL},
}{\fs22{\b ENV}, }and {\fs22{\b MAIL }}are
not set at all by the shell (although {\fs22{\b HOME }}{\i is
}set by {\i login}(1)). On some systems {\fs22{\b MAIL }}and
{\fs22{\b SHELL }}are also set by {\i login}(1). {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Field.Splitting} Field
\~Splitting. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}After parameter
expansion and command substitution, the results of substitutions are scanned
for the field separator characters (those found in {\fs22{\b IFS\~}})
and split into distinct fields where such characters are found. Explicit
null fields (\~{\b "\~"} or {\b '\~'}\~)
are retained. Implicit null fields (those resulting from {\i parameters }that
have no values or command substitutions with no output) are removed. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.File.Name.Generation} File
\~Name \~Generation. \~\~\~}\par\pard\qc\li840\tx840\tx20000}}Following
splitting, each field is scanned for the characters {\b *}, {\b ?},
{\b (}, and {\b [\~}unless the {\b\'2d f }option
has been set. If one of these characters appears, then the word is regarded
as a {\i pattern}. Each file name component that contains any pattern character
is replaced with a lexicographically sorted set of names that matches the
pattern from that directory. If no file name is found that matches the pattern,
then that component of the filename is left unchanged. If {\fs22{\b FIGNORE
}}is set, then each file name component that matches the pattern
defined by the value of {\fs22{\b FIGNORE }}is ignored
when generating the matching filenames. The names {\b . }and {\b ..
}are also ignored. If {\fs22{\b FIGNORE }}is not
set, the character {\b . }at the start of each file name component
will be ignored unless the first character of the pattern corresponding
to this component is the character {\b . }itself. Note, that for
other uses of pattern matching the {\b / }and {\b . }are
not treated specially. {\b\par\pard\qc\li1400\tx1400\tx20000\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 * }\tab Matches any
string, including the null string. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 ? }\tab Matches any single
character. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b [\~}\~.\~.\~.\~{\b\~ ]
}\tab Matches any one of the enclosed characters. A pair of characters
separated by {\b\'2d }matches any character lexically between
the pair, inclusive. If the first character following the opening {\b [\~}is
a {\b ! }then any character not enclosed is matched. A {\b\'2d
}can be included in the character set by putting it as the first or
last character. \line Within {\b [\~}and {\b\~ ]\~},
character classes can be specified with the syntax {\b [:}{\i class}{\b :]}
where class is one of the following classes defined in the ANSI-C standard:
{\b\line alnum alpha blank cntrl digit graph lower print punct space upper
xdigit }\line Within {\b [\~}and {\b\~ ]\~},
an equivalence class can be specified with the syntax {\b [=}{\i c}{\b =]}
which matches all characters with the same primary collation weight (as
defined by the current locale) as the character {\i c}. \line Within {\b [\~}and
{\b\~ ]\~}, {\b [.}{\i symbol}{\b .]}
matches the collating symbol {\i symbol}. A {\i pattern-list }is
a list of one or more patterns separated from each other with a {\b&
}or {\b |}. A {\b& }signifies that all patterns
must be matched whereas {\b | }requires that only one pattern be
matched. Composite patterns can be formed with one or more of the following
sub-patterns: {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 ?(}{\i pattern-list\~}{\b )}
\tab Optionally matches any one of the given patterns. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 *(}{\i pattern-list\~}{\b )}
\tab Matches zero or more occurrences of the given patterns. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 +(}{\i pattern-list\~}{\b )}
\tab Matches one or more occurrences of the given patterns. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 @(}{\i pattern-list\~}{\b )}
\tab Matches exactly one of the given patterns. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 !(}{\i pattern-list\~}{\b )}
\tab Matches anything except one of the given patterns. Each sub-pattern
in a composite pattern is numbered, starting at 1, by the location of the
{\b (} within the pattern. The sequence {\b\'5c}{\i n\~},
where {\i n\~}is a single digit and {\b\'5c}{\i n\~}comes
after the {\i n}-th. sub-pattern, matches the same string as the sub-pattern
itself. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Quoting} Quoting. \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}Each
of the {\i metacharacters }listed earlier (see {\uldb Definitions}{\v HTML2RTF.Definitions}{\*\comment{\i Definitions
}}above) has a special meaning to the shell and causes termination of
a word unless quoted. A character may be {\i quoted }(i.e., made to stand
for itself) by preceding it with a {\b\'5c}. The pair {\b\'5c new-line
}is removed. All characters enclosed between a pair of single quote
marks (\~{\b '\~'}\~) that is not preceded by a {\b $
}are quoted. A single quote cannot appear within the single quotes.
A single quoted string preceded by an unquoted {\b $ }is processed
as an ANSI-C string except that {\b\'5c 0 }within the string
causes the remainder of the string to be ignored and {\b\'5c E }is
equivalent to the escape character (ascii {\b 033}). Inside double
quote marks ({\b "\~"}), parameter and command substitution
occur and {\b\'5c }quotes the characters {\b\'5c},
{\b{\fs26 `}}, {\b "}, and {\b $}.
A {\b $ }in front of a double quoted string will be ignored in
the "C" or "POSIX" locale, and may cause the string to be replaced by a
locale specific string otherwise. The meaning of {\b $* }and {\b $@
}is identical when not quoted or when used as a variable assignment
value or as a file name. However, when used as a command argument, {\b "$*"
}is equivalent to {\b "$1}{\i d}{\b\~ $2}{\i d}\~.\~.\~.{\b "},
where {\i d }is the first character of the {\fs22{\b IFS }}variable,
whereas {\b "$@" }is equivalent to {\b "$1"\~}{\b "$2"\~}.\~.\~.\~.
Inside grave quote marks ({\b{\fs26 `}\~{\fs26 `}}),
{\b\'5c }quotes the characters {\b\'5c}, {\b{\fs26 `}},
and {\b $}. If the grave quotes occur within double quotes, then
{\b\'5c }also quotes the character {\b "}. \par\pard\qc\li840\tx840\tx20000 The special
meaning of reserved words or aliases can be removed by quoting any character
of the reserved word. The recognition of function names or built-in command
names listed below cannot be altered by quoting them. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Arithmetic.Evaluation} Arithmetic
\~Evaluation. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}The shell performs
arithmetic evaluation for arithmetic substitution, to evaluate an arithmetic
command, to evaluate an indexed array subscript, and to evaluate arguments
to the built-in commands {\b shift }and {\b let}. Evaluations
are performed using double precision floating point arithmetic. Floating
point constants follow the ANSI-C programming language conventions. Integer
constants are of the form [\~{\i base}{\b #\~}\~]{\i n\~}where
{\i base }is a decimal number between two and sixty-four representing the
arithmetic base and {\i n }is a number in that base. The digits above 9
are represented by the lower case letters, the upper case letters, {\b @},
and {\b _ }respectively. For bases less than or equal to 36, upper
and lower case characters can be used interchangeably. If {\i base }is
omitted, then base 10 is used. \par\pard\qc\li840\tx840\tx20000 An arithmetic expression uses the same
syntax, precedence, and associativity of expression as the C language. All
the C language operators that apply to floating point quantities can be
used. In addition, when the value of an arithmetic variable or sub-expression
can be represented as a long integer, all C language integer arithmetic
operations can be performed. Variables can be referenced by name within
an arithmetic expression without using the parameter expansion syntax. When
a variable is referenced, its value is evaluated as an arithmetic expression.
\par\pard\qc\li840\tx840\tx20000 The following math library functions can be used with an arithmetic expression:
{\b\par\pard\qc\li1120\tx1120\tx20000 abs acos asin atan cos cosh exp int log sin sinh sqrt tan
tanh }\par\pard\qc\li840\tx840\tx20000 An internal representation of a {\i variable }as a double
precision floating point can be specified with the {\b\'2d E}
[\~{\i n\~}\~] or {\b\'2d F} [\~{\i n\~}\~]
option of the {\b typeset }special built-in command. The {\b\'2d E
}option causes the expansion of the value to be represented using
scientific notation when it is expanded. The optional option argument {\i n
}defines the number of significant figures. The {\b\'2d F }option
causes the expansion to be represented as a floating decimal number when
it is expanded. The optional option argument {\i n }defines the number
of places after the decimal point in this case. \par\pard\qc\li840\tx840\tx20000 An internal integer representation
of a {\i variable }can be specified with the {\b\'2d i} [\~{\i n\~}\~]
option of the {\b typeset }special built-in command. The optional
option argument {\i n }specifies an arithmetic base to be used when expanding
the variable. If you do not specify an arithmetic base, the first assignment
to the variable determines the arithmetic base. \par\pard\qc\li840\tx840\tx20000 Arithmetic evaluation
is performed on the value of each assignment to a variable with the {\b\'2d E},
{\b\'2d F}, or {\b\'2d i }attribute. Assigning
a floating point number to a variable whose type is an integer causes the
fractional part to be truncated. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Prompting} Prompting.
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}When used interactively,
the shell prompts with the value of {\fs22{\b PS1 }}after
expanding it for parameter expansion, command substitution, and arithmetic
substitution, before reading a command. In addition, each single {\b !
}in the prompt is replaced by the command number. A {\b !! }is
required to place {\b ! }in the prompt. If at any time a new-line
is typed and further input is needed to complete a command, then the secondary
prompt (i.e., the value of {\b{\fs22 PS2}}) is issued.
{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Conditional.Expressions} Conditional \~Expressions.
\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}A {\i conditional expression }is
used with the {\b [[ }compound command to test attributes of files
and to compare strings. Field splitting and file name generation are not
performed on the words between {\b [[ }and {\b ]]}. Each
expression can be constructed from one or more of the following unary or
binary expressions: {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 string} \tab True, if {\i string }is
not null. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d a} {\i file} \tab Same as {\b\'2d e}
below. This is obsolete. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d b} {\i file} \tab True, if
{\i file }exists and is a block special file. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d c}
{\i file} \tab True, if {\i file }exists and is a character special file.
{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d d} {\i file} \tab True, if {\i file }exists and is
a directory. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d e} {\i file} \tab True, if {\i file }exists.
{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d f} {\i file} \tab True, if {\i file }exists and is
an ordinary file. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d g} {\i file} \tab True, if {\i file
}exists and it has its setgid bit set. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d k} {\i file}
\tab True, if {\i file }exists and it has its sticky bit set. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d n}
{\i string} \tab True, if length of {\i string }is non-zero. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d o}
{\i option} \tab True, if option named {\i option }is on. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d p}
{\i file} \tab True, if {\i file }exists and is a fifo special file or a
pipe. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d r} {\i file} \tab True, if {\i file }exists
and is readable by current process. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d s} {\i file}
\tab True, if {\i file }exists and has size greater than zero. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d t}
{\i fildes} \tab True, if file descriptor number {\i fildes }is open and
associated with a terminal device. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d u} {\i file}
\tab True, if {\i file }exists and it has its setuid bit set. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d w}
{\i file} \tab True, if {\i file }exists and is writable by current process.
{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d x} {\i file} \tab True, if {\i file }exists and is
executable by current process. If {\i file }exists and is a directory,
then true if the current process has permission to search in the directory.
{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d z} {\i string} \tab True, if length of {\i string }is
zero. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d L} {\i file} \tab True, if {\i file }exists
and is a symbolic link. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d O} {\i file} \tab True, if
{\i file }exists and is owned by the effective user id of this process.
{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d G} {\i file} \tab True, if {\i file }exists and its
group matches the effective group id of this process. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d S}
{\i file} \tab True, if {\i file }exists and is a socket. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 file1}
{\b\'2d nt} {\i file2} \tab True, if {\i file1 }exists and
{\i file2 }does not, or {\i file1 }is newer than {\i file2}. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 file1}
{\b\'2d ot} {\i file2} \tab True, if {\i file2 }exists and
{\i file1 }does not, or {\i file1 }is older than {\i file2}. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 file1}
{\b\'2d ef} {\i file2} \tab True, if {\i file1 }and {\i file2
}exist and refer to the same file. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 string} {\b ==} {\i pattern}
\tab True, if {\i string }matches {\i pattern}. Any part of {\i pattern }can
be quoted to cause it to be matched as a string. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 string} {\b =}
{\i pattern} \tab Same as {\b ==} above, but is obsolete. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 string}
{\b !=} {\i pattern} \tab True, if {\i string }does not match {\i pattern}.
{\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 string1} {\b<} {\i string2} \tab True, if {\i string1 }comes
before {\i string2 }based on ASCII value of their characters. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 string1}
{\b>} {\i string2} \tab True, if {\i string1 }comes after {\i string2
}based on ASCII value of their characters. \line The following obsolete
arithmetic comparisons are also permitted: {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 exp1} {\b\'2d eq}
{\i exp2} \tab True, if {\i exp1 }is equal to {\i exp2}. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 exp1} {\b\'2d ne}
{\i exp2} \tab True, if {\i exp1 }is not equal to {\i exp2}. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 exp1}
{\b\'2d lt} {\i exp2} \tab True, if {\i exp1 }is less than
{\i exp2}. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 exp1} {\b\'2d gt} {\i exp2} \tab True, if
{\i exp1 }is greater than {\i exp2}. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 exp1} {\b\'2d le}
{\i exp2} \tab True, if {\i exp1 }is less than or equal to {\i exp2}. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 exp1}
{\b\'2d ge} {\i exp2} \tab True, if {\i exp1 }is greater than
or equal to {\i exp2}. \par\pard\qc\li840\tx840\tx20000 In each of the above expressions, if {\i file
}is of the form {\b /dev/fd/}{\i n}, where {\i n }is an integer,
then the test is applied to the open file whose descriptor number is {\i n}.
\par\pard\qc\li840\tx840\tx20000 A compound expression can be constructed from these primitives by using
any of the following, listed in decreasing order of precedence. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 (}{\i expression}{\b )}
\tab True, if {\i expression }is true. Used to group expressions. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 !}
{\i expression} \tab True if {\i expression }is false. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 expression1}
{\b&&} {\i expression2} \tab True, if {\i expression1 }and
{\i expression2 }are both true. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 expression1} {\b ||} {\i expression2}
\tab True, if either {\i expression1 }or {\i expression2 }is true. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Input.Output} Input/Output.
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}Before a command is executed,
its input and output may be redirected using a special notation interpreted
by the shell. The following may appear anywhere in a simple-command or may
precede or follow a {\i command }and are {\i not }passed on to the invoked
command. Command substitution, parameter expansion, and arithmetic substitution
occur before {\i word }or {\i digit }is used except as noted below. File
name generation occurs only if the shell is interactive and the pattern
matches a single file. Field splitting is not performed. \par\pard\qc\li840\tx840\tx20000 In each of the
following redirections, if {\i file }is of the form {\b /dev/tcp/}{\i host}{\b /}{\i port},
or {\b /dev/udp/}{\i host}{\b /}{\i port}, where {\i host
}is a hostname or host address, and {\i port }is an integer port number,
then the redirection attempts to make a {\b tcp} or {\b udp}
connection to the corresponding socket. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b<}{\i word
}\tab Use file {\i word }as standard input (file descriptor 0). \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b>}{\i word
}\tab Use file {\i word }as standard output (file descriptor 1). If the
file does not exist then it is created. If the file exists, and the {\b noclobber
}option is on, this causes an error; otherwise, it is truncated to
zero length. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b> |}{\i word }\tab Sames as {\b>},
except that it overrides the {\b noclobber }option. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b>>}{\i word
}\tab Use file {\i word }as standard output. If the file exists, then output
is appended to it (by first seeking to the end-of-file); otherwise, the
file is created. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b<>}{\i word }\tab Open file {\i word }for
reading and writing as standard input. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000<<}[\~{\b\'2d}\~]{\i word}
\tab The shell input is read up to a line that is the same as {\i word }after
any quoting has been removed, or to an end-of-file. No parameter substitution,
command substitution, arithmetic substitution or file name generation is
performed on {\i word}. The resulting document, called a {\i here-document},
becomes the standard input. If any character of {\i word }is quoted, then
no interpretation is placed upon the characters of the document; otherwise,
parameter expansion, command substitution, and arithmetic substitution occur,
{\b\'5c new-line }is ignored, and {\b\'5c }must
be used to quote the characters {\b\'5c}, {\b $},
{\b{\fs26 `}}. If {\b\'2d }is appended
to {\b<<}, then all leading tabs are stripped from {\i word
}and from the document. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b<&}{\i digit }\tab The standard
input is duplicated from file descriptor {\i digit }(see {\i dup}(2)).
Similarly for the standard output using {\b>&\~}{\i digit}.
\par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b<&}{\i digit}{\b\'2d }\tab The file descriptor
given by {\i digit }is moved to standard input. Similarly for the standard
output using {\b>&\~}{\i digit}{\b\'2d}.
{\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000<&\'2d }\tab The standard input is closed. Similarly
for the standard output using {\b>&\'2d}. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000<& p
}\tab The input from the co-process is moved to standard input. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000>& p
}\tab The output to the co-process is moved to standard output. \par\pard\qc\li840\tx840\tx20000 If
one of the above is preceded by a digit, then the file descriptor number
referred to is that specified by the digit (instead of the default 0 or
1). For example: {\b\par\pard\qc\li1120\tx1120\tx20000 .\~.\~. \~2>&1}
\par\pard\qc\li840\tx840\tx20000 means file descriptor 2 is to be opened for writing as a duplicate
of file descriptor 1. \par\pard\qc\li840\tx840\tx20000 The order in which redirections are specified is
significant. The shell evaluates each redirection in terms of the ({\i file
descriptor}, {\i file}) association at the time of evaluation. For example:
{\b\par\pard\qc\li1120\tx1120\tx20000 .\~.\~. \~1>}{\i fname\~}{\b 2>&1}
\par\pard\qc\li840\tx840\tx20000 first associates file descriptor 1 with file {\i fname\~}. It
then associates file descriptor 2 with the file associated with file descriptor
1 (i.e. {\i fname\~}). If the order of redirections were reversed,
file descriptor 2 would be associated with the terminal (assuming file descriptor
1 had been) and then file descriptor 1 would be associated with file {\i fname\~}.
\par\pard\qc\li840\tx840\tx20000 If a command is followed by {\b& }and job control is not active,
then the default standard input for the command is the empty file {\b /dev/null}.
Otherwise, the environment for the execution of a command contains the file
descriptors of the invoking shell as modified by input/output specifications.
{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Environment} Environment. \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}The
{\i environment }(see {\i environ}(7)) is a list of name-value
pairs that is passed to an executed program in the same way as a normal
argument list. The names must be {\i identifiers }and the values are character
strings. The shell interacts with the environment in several ways. On invocation,
the shell scans the environment and creates a variable for each name found,
giving it the corresponding value and attributes and marking it {\i export}.
Executed commands inherit the environment. If the user modifies the values
of these variables or creates new ones, using the {\b export }or
{\b typeset \'2dx }commands, they become part of the environment.
The environment seen by any executed command is thus composed of any name-value
pairs originally inherited by the shell, whose values may be modified by
the current shell, plus any additions which must be noted in {\b export
}or {\b typeset \'2dx }commands. \par\pard\qc\li840\tx840\tx20000 The environment for
any {\i simple-command }or function may be augmented by prefixing it with
one or more variable assignments. A variable assignment argument is a word
of the form {\i identifier=value}. Thus: {\b{\fs22\par\pard\qc\li1120\tx1120\tx20000 TERM}=450
\~cmd \~args} and {\b\line (export \~{\fs22 TERM};
\~{\fs22 TERM}=450; \~cmd \~args)} \par\pard\qc\li840\tx840\tx20000 are equivalent
(as far as the above execution of {\i cmd }is concerned except for special
built-in commands listed below \'2d those that are preceded with a dagger).
\par\pard\qc\li840\tx840\tx20000 If the obsolete {\b\'2d k }option is set, {\i all }variable
assignment arguments are placed in the environment, even if they occur after
the command name. The following first prints {\b a=b c }and then
{\b c}: \line
{\b\~\~\~\~\~\~\~\~echo\~\~a=b\~\~c\~\~\~\~\line
\~\~\~\~\~\~\~\~set\~\~\'2dk\~\line
\~\~\~\~\~\~\~\~echo\~\~a=b\~\~c\~\~\~\~\line
}This
feature is intended for use with scripts written for early versions of the
shell and its use in new scripts is strongly discouraged. It is likely to
disappear someday. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Functions} Functions. \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}For
historical reasons, there are two ways to define functions, the {\i name}{\b (\~)
}syntax and the {\b function }{\i name }syntax, described
in the {\i Commands }section above. Shell functions are read in and stored
internally. Alias names are resolved when the function is read. Functions
are executed like commands with the arguments passed as positional parameters.
(See {\i Execution }below.) \par\pard\qc\li840\tx840\tx20000 Functions defined by the {\b function
}{\i name }syntax and called by name execute in the same process
as the caller and share all files and present working directory with the
caller. Traps caught by the caller are reset to their default action inside
the function. A trap condition that is not caught or ignored by the function
causes the function to terminate and the condition to be passed on to the
caller. A trap on {\fs22{\b EXIT }}set inside a function
is executed in the environment of the caller after the function completes.
Ordinarily, variables are shared between the calling program and the function.
However, the {\b typeset }special built-in command used within
a function defines local variables whose scope includes the current function
and all functions it calls. Errors within functions return control to the
caller. \par\pard\qc\li840\tx840\tx20000 Functions defined with the {\i name}{\b (\~) }syntax
and functions defined with the {\b function }{\i name }syntax
that are invoked with the {\b{\fs26 .}} special built-in
are executed in the caller's environment and share all variables and traps
with the caller. Errors within these function executions cause the script
that contains them to abort. \par\pard\qc\li840\tx840\tx20000 The special built-in command {\b return
}is used to return from function calls. \par\pard\qc\li840\tx840\tx20000 Function names can be listed
with the {\b\'2d f }or {\b +f }option of the {\b typeset
}special built-in command. The text of functions, when available,
will also be listed with {\b\'2d f}. Functions can be undefined
with the {\b\'2d f }option of the {\b unset }special
built-in command. \par\pard\qc\li840\tx840\tx20000 Ordinarily, functions are unset when the shell executes
a shell script. Functions that need to be defined across separate invocations
of the shell should be placed in a directory and the {\b{\fs22 FPATH
}}variable should contain the name of this directory. They may
also be specified in the {\b{\fs22 ENV }}file. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Discipline.Functions} Discipline
\~Functions. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}Each variable
can have zero or more discipline functions associated with it. The shell
initially understands the discipline names {\b get}, {\b set},
and {\b unset} but on most systems others can be added at run time
via the C programming interface extension provided by the {\b builtin
}built-in utility. If the {\b get} discipline is defined
for a variable, it is invoked whenever the given variable is referenced.
If the variable {\b .sh.value} is assigned a value inside the discipline
function, the referenced variable will evaluate to this value instead. If
the {\b set} discipline is defined for a variable, it is invoked
whenever the given variable is assigned a value. The variable {\b .sh.value}
is given the value of the variable before invoking the discipline, and the
variable will be assigned the value of {\b .sh.value} after the
discipline completes. If {\b .sh.value} is unset inside the discipline,
then that value is unchanged. If the {\b unset} discipline is defined
for a variable, it is invoked whenever the given variable is unset. The
variable will not be unset unless it is unset explicitly from within this
discipline function. \par\pard\qc\li840\tx840\tx20000 The variable {\b .sh.name }contains the
name of the variable for which the discipline function is called, {\b .sh.subscript
}is the subscript of the variable, and {\b .sh.value }will
contain the value being assigned inside the {\b .set }discipline
function. For the {\b set} discipline, changing {\b .sh.value
}will change the value that gets assigned. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Jobs} Jobs.
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}If the {\b monitor }option
of the {\b set }command is turned on, an interactive shell associates
a {\i job} with each pipeline. It keeps a table of current jobs, printed
by the {\b jobs }command, and assigns them small integer numbers.
When a job is started asynchronously with {\b&}, the shell prints
a line which looks like: \par\pard\qc\li840\tx840\tx20000 [1] 1234 \par\pard\qc\li840\tx840\tx20000 indicating that the job which was
started asynchronously was job number 1 and had one (top-level) process,
whose process id was 1234. \par\pard\qc\li840\tx840\tx20000 This paragraph and the next require features
that are not in all versions of UNIX and may not apply. If you are running
a job and wish to do something else you may hit the key {\b ^Z}
(control-Z) which sends a STOP signal to the current job. The shell will
then normally indicate that the job has been `Stopped', and print another
prompt. You can then manipulate the state of this job, putting it in the
background with the {\b bg }command, or run some other commands
and then eventually bring the job back into the foreground with the foreground
command {\b fg}. A {\b ^Z} takes effect immediately and
is like an interrupt in that pending output and unread input are discarded
when it is typed. \par\pard\qc\li840\tx840\tx20000 A job being run in the background will stop if it tries
to read from the terminal. Background jobs are normally allowed to produce
output, but this can be disabled by giving the command {\b stty tostop}.
If you set this tty option, then background jobs will stop when they try
to produce output like they do when they try to read input. \par\pard\qc\li840\tx840\tx20000 There are
several ways to refer to jobs in the shell. A job can be referred to by
the process id of any process of the job or by one of the following: \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b %}{\i number
}\tab The job with the given number. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b %}{\i string }\tab Any
job whose command line begins with {\i string}. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b %?}{\i string
}\tab Any job whose command line contains {\i string}. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b %% }\tab Current
job. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b %+ }\tab Equivalent to {\b %%}. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b %\'2d
}\tab Previous job. \par\pard\qc\li840\tx840\tx20000 The shell learns immediately whenever a process
changes state. It normally informs you whenever a job becomes blocked so
that no further progress is possible, but only just before it prints a prompt.
This is done so that it does not otherwise disturb your work. The {\b notify
}option of the {\b set }command causes the shell to print
these job change messages as soon as they occur. \par\pard\qc\li840\tx840\tx20000 When the {\b monitor
}option is on, each background job that completes triggers any trap
set for {\b CHLD}. \par\pard\qc\li840\tx840\tx20000 When you try to leave the shell while jobs
are running or stopped, you will be warned that `You have stopped(running)
jobs.' You may use the {\b jobs }command to see what they are.
If you immediately try to exit again, the shell will not warn you a second
time, and the stopped jobs will be terminated. When a login shell receives
a HUP signal, it sends a HUP signal to each job that has not been disowned
with the {\b disown }built-in command described below. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Signals} Signals.
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}The {\fs22 INT}
and {\fs22 QUIT} signals for an invoked command are ignored if the
command is followed by {\b& }and the {\b monitor }option
is not active. Otherwise, signals have the values inherited by the shell
from its parent (but see also the {\b trap }built-in command below).
{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Execution} Execution. \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}Each
time a command is read, the above substitutions are carried out. If the
command name matches one of the {\i Special Built-in Commands }listed below,
it is executed within the current shell process. Next, the command name
is checked to see if it matches a user defined function. If it does, the
positional parameters are saved and then reset to the arguments of the {\i function
}call. A function is also executed in the current shell process. When
the {\i function }completes or issues a {\b return}, the positional
parameter list is restored. For functions defined with the {\b function
}{\i name }syntax, any trap set on {\fs22{\b EXIT }}within
the function is executed. The exit value of a {\i function }is the value
of the last command executed. If a command name is not a {\i special built-in
command }or a user defined {\i function}, but it is one of the built-in
commands listed below, it is executed in the current shell process. \par\pard\qc\li840\tx840\tx20000 The
shell variable {\b{\fs22 PATH }}defines the search path
for the directory containing the command. Alternative directory names are
separated by a colon ({\b :}). The default path is {\b /bin:/usr/bin:
}(specifying {\b /bin}, {\b /usr/bin}, and the current
directory in that order). The current directory can be specified by two
or more adjacent colons, or by a colon at the beginning or end of the path
list. If the command name contains a {\b /}, then the search path
is not used. Otherwise, each directory in the path is searched for an executable
file that is not a directory. If the shell determines that there is a built-in
version of a command corresponding to a given pathname, this built-in is
invoked in the current process. A process is created and an attempt is made
to execute the command via {\i exec}(2). If the file has execute permission
but is not an {\b a.out }file, it is assumed to be a file containing
shell commands. A separate shell is spawned to read it. All non-exported
variables are removed in this case. If the shell command file doesn't have
read permission, or if the {\i setuid }and/or {\i setgid }bits are set
on the file, then the shell executes an agent whose job it is to set up
the permissions and execute the shell with the shell command file passed
down as an open file. A parenthesized command is executed in a sub-shell
without removing non-exported variables. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Command.Re.entry} Command
\~Re-entry. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}The text of the
last {\b{\fs22 HISTSIZE }}(default 128) commands entered
from a terminal device is saved in a {\i history }file. The file {\b{\fs22 $HOME}/.sh_history
}is used if the {\b{\fs22 HISTFILE }}variable is
not set or if the file it names is not writable. A shell can access the
commands of all {\i interactive }shells which use the same named {\fs22{\b HISTFILE}.
}The built-in command {\b hist }is used to list or edit a portion
of this file. The portion of the file to be edited or listed can be selected
by number or by giving the first character or characters of the command.
A single command or range of commands can be specified. If you do not specify
an editor program as an argument to {\b hist }then the value of
the variable {\fs22{\b HISTEDIT }}is used. If {\fs22{\b HISTEDIT
}}is unset, the obsolete variable {\fs22{\b FCEDIT }}is
used. If {\fs22{\b FCEDIT }}is not defined, then {\b /bin/ed
}is used. The edited command(s) is printed and re-executed upon leaving
the editor unless you quit without writing. The {\b\'2d s }option
(and in obsolete versions, the editor name {\b\'2d\~})
is used to skip the editing phase and to re-execute the command. In this
case a substitution parameter of the form {\i old}{\b =}{\i new}
can be used to modify the command before execution. For example, with the
preset alias {\b r}, which is aliased to {\b 'hist \'2ds'},
typing `{\b r bad=good c}' will re-execute the most recent command
which starts with the letter {\b c}, replacing the first occurrence
of the string {\b bad }with the string {\b good}. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.In.line.Editing.Options} In-line
\~Editing \~Options. \~\~\~}\par\pard\qc\li840\tx840\tx20000}}Normally,
each command line entered from a terminal device is simply typed followed
by a {\b new-line} (`RETURN' or `LINE\~FEED'). If either the
{\b emacs}, {\b gmacs}, or {\b vi }option is
active, the user can edit the command line. To be in either of these edit
modes {\b set }the corresponding option. An editing option is automatically
selected each time the {\fs22{\b VISUAL }}or {\fs22{\b EDITOR
}}variable is assigned a value ending in either of these option
names. \par\pard\qc\li840\tx840\tx20000 The editing features require that the user's terminal accept `RETURN'
as carriage return without line feed and that a space (`\~') must overwrite
the current character on the screen. \par\pard\qc\li840\tx840\tx20000 The editing modes implement a concept
where the user is looking through a window at the current line. The window
width is the value of {\fs22{\b COLUMNS }}if it is defined,
otherwise 80. If the window width is too small to display the prompt and
leave at least 8 columns to enter input, the prompt is truncated from the
left. If the line is longer than the window width minus two, a mark is displayed
at the end of the window to notify the user. As the cursor moves and reaches
the window boundaries the window will be centered about the cursor. The
mark is a {\b>} (<{\b , }{\b *}) if the line
extends on the right (left, both) side(s) of the window. \par\pard\qc\li840\tx840\tx20000 The search commands
in each edit mode provide access to the history file. Only strings are matched,
not patterns, although a leading {\b ^ }in the string restricts
the match to begin at the first character in the line. \par\pard\qc\li840\tx840\tx20000 Each of the edit
modes has an operation to list the files or commands that match a partially
entered word. When applied to the first word on the line, or the first word
after a {\b ;}, {\b |}, {\b&}, or {\b (},
and the word does not begin with {\b ~ }or contain a {\b /},
the list of aliases, functions, and executable commands defined by the {\b{\fs22 PATH
}}variable that could match the partial word is displayed. Otherwise,
the list of files that match the given word is displayed. If the partially
entered word does not contain any file expansion characters, a {\b *
}is appended before generating these lists. After displaying the generated
list, the input line is redrawn. These operations are called command name
listing and file name listing, respectively. There are additional operations,
referred to as command name completion and file name completion, which compute
the list of matching commands or files, but instead of printing the list,
replace the current word with a complete or partial match. For file name
completion, if the match is unique, a {\b / }is appended if the
file is a directory and a space is appended if the file is not a directory.
Otherwise, the longest common prefix for all the matching files replaces
the word. For command name completion, only the portion of the file names
after the last {\b / }are used to find the longest command prefix.
If only a single name matches this prefix, then the word is replaced with
the command name followed by a space. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Key.Bindings} Key
\~Bindings. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}The {\b{\fs22 KEYBD
}}trap can be used to intercept keys as they are typed and change
the characters that are actually seen by the shell. This trap is executed
after each character (or sequence of characters when the first character
is ESC) is entered while reading from a terminal. The variable {\b .sh.edchar
}contains the character or character sequence which generated the
trap. Changing the value of {\b .sh.edchar }in the trap action
causes the shell to behave as if the new value were entered from the keyboard
rather than the original value. \par\pard\qc\li840\tx840\tx20000 The variable {\b .sh.edcol }is
set to the input column number of the cursor at the time of the input. The
variable {\b .sh.edmode }is set to ESC when in {\b vi }insert
mode (see below) and is null otherwise. By prepending {\b $\{.sh.editmode\}
}to a value assigned to {\b .sh.edchar }it will cause the
shell to change to control mode if it is not already in this mode. \par\pard\qc\li840\tx840\tx20000 This
trap is not invoked for characters entered as arguments to editing directives,
or while reading input for a character search. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Emacs.Editing.Mode} Emacs
\~Editing \~Mode. \~\~\~}\par\pard\qc\li840\tx840\tx20000}}This mode
is entered by enabling either the {\b emacs }or {\b gmacs }option.
The only difference between these two modes is the way they handle {\b ^T}.
To edit, the user moves the cursor to the point needing correction and then
inserts or deletes characters or words as needed. All the editing commands
are control characters or escape sequences. The notation for control characters
is caret ({\b ^}) followed by the character. For example, {\b ^F
}is the notation for control {\b F}. This is entered by depressing
`f' while holding down the `CTRL' (control) key. The `SHIFT' key is {\i not
}depressed. (The notation {\b ^? }indicates the DEL (delete)
key.) \par\pard\qc\li840\tx840\tx20000 The notation for escape sequences is {\b M- }followed by
a character. For example, {\b M-f }(pronounced Meta f) is entered
by depressing ESC (ascii {\b 033}) followed by `f'. ({\b M-F
}would be the notation for ESC followed by `SHIFT' (capital) `F'.)
\par\pard\qc\li840\tx840\tx20000 All edit commands operate from any place on the line (not just at the
beginning). Neither the `RETURN' nor the `LINE FEED' key is entered after
edit commands except when noted. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^F }\tab Move cursor
forward (right) one character. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-f }\tab Move cursor forward
one word. (The {\b emacs }editor's idea of a word is a string of
characters consisting of only letters, digits and underscores.) \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^B
}\tab Move cursor backward (left) one character. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-b }\tab Move
cursor backward one word. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^A }\tab Move cursor to start of
line. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^E }\tab Move cursor to end of line. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^]}{\i char
}\tab Move cursor forward to character {\i char }on current line. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-^]}{\i char
}\tab Move cursor backward to character {\i char }on current line. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^X^X
}\tab Interchange the cursor and mark. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 erase }\tab (User defined
erase character as defined by the {\i stty}(1) command, usually {\b ^H
}or {\b #}.) Delete previous character. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^D }\tab Delete
current character. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-d }\tab Delete current word. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-^H
}\tab (Meta-backspace) Delete previous word. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-h }\tab Delete
previous word. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-^? }\tab (Meta-DEL) Delete previous word (if
your interrupt character is {\b ^? }(DEL, the default) then this
command will not work). \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^T }\tab Transpose current character
with previous character and advance the cursor in {\i emacs }mode. Transpose
two previous characters in {\i gmacs }mode. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^C }\tab Capitalize
current character. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-c }\tab Capitalize current word. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-l
}\tab Change the current word to lower case. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^K }\tab Delete
from the cursor to the end of the line. If preceded by a numerical parameter
whose value is less than the current cursor position, then delete from given
position up to the cursor. If preceded by a numerical parameter whose value
is greater than the current cursor position, then delete from cursor up
to given cursor position. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^W }\tab Kill from the cursor to
the mark. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-p }\tab Push the region from the cursor to the
mark on the stack. {\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 kill }\tab (User defined kill character as defined
by the stty command, usually {\b ^G }or {\b @}.) Kill
the entire current line. If two {\i kill }characters are entered in succession,
all kill characters from then on cause a line feed (useful when using paper
terminals). \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^Y }\tab Restore last item removed from line. (Yank
item back to the line.) \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^L }\tab Line feed and print current
line. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^@ }\tab (Null character) Set mark. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-}{\i space
}\tab (Meta space) Set mark. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^J }\tab (New\~line) Execute
the current line. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^M }\tab (Return) Execute the current line.
{\i\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 eof }\tab End-of-file character, normally {\b ^D}, is processed
as an End-of-file only if the current line is null. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^P }\tab Fetch
previous command. Each time {\b ^P }is entered the previous command
back in time is accessed. Moves back one line when not on the first line
of a multi-line command. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-< }\tab Fetch the least recent
(oldest) history line. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-> }\tab Fetch the most recent (youngest)
history line. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^N }\tab Fetch next command line. Each time {\b ^N
}is entered the next command line forward in time is accessed. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^R}{\i string
}\tab Reverse search history for a previous command line containing {\i string}.
If a parameter of zero is given, the search is forward. {\i String }is
terminated by a `RETURN' or `NEW\~LINE'. If string is preceded by a
{\b ^}, the matched line must begin with {\i string}. If {\i string
}is omitted, then the next command line containing the most recent {\i string
}is accessed. In this case a parameter of zero reverses the direction
of the search. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 ^O }\tab Operate \'2d Execute the current
line and fetch the next line relative to current line from the history file.
\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-}{\i digits }\tab (Escape) Define numeric parameter, the
digits are taken as a parameter to the next command. The commands that accept
a parameter are {\b ^F}, {\b ^B}, {\i erase}, {\b ^C},
{\b ^D}, {\b ^K}, {\b ^R}, {\b ^P},
{\b ^N}, {\b ^]}, {\b M-.}, {\b M-^]},
{\b M-_}, {\b M-b}, {\b M-c}, {\b M-d},
{\b M-f}, {\b M-h}, {\b M-l }and {\b M-^H}.
\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-}{\i letter }\tab Soft-key \'2d Your alias list is searched
for an alias by the name {\b _}{\i letter }and if an alias of
this name is defined, its value will be inserted on the input queue. The
{\i letter }must not be one of the above meta-functions. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b M-[}{\i letter
}\tab Soft-key \'2d Your alias list is searched for an alias by the
name {\b __}{\i letter }and if an alias of this name is defined,
its value will be inserted on the input queue. The can be used to program
functions keys on many terminals. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 M-. }\tab The last word of
the previous command is inserted on the line. If preceded by a numeric parameter,
the value of this parameter determines which word to insert rather than
the last word. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 M-_ }\tab Same as {\b M-.}. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 M-*
}\tab Attempt file name generation on the current word. An asterisk
is appended if the word doesn't match any file or contain any special pattern
characters. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 M-ESC }\tab Command or file name completion as
described above. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 M-= }\tab Command or file name listing as
described above. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b ^U }\tab Multiply parameter of next command
by 4. \par\pard\qc\fi-560\li1120\tx1120\tx20000{\b\'5c }\tab Escape next character. Editing characters,
the user's erase, kill and interrupt (normally {\b ^?}) characters
may be entered in a command line or in a search string if preceded by a
{\b\'5c}. The {\b\'5c }removes the next character's
editing features (if any). {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 ^V }\tab Display version of the
shell. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 M-# }\tab If the line does not begin with a {\b #},
a {\b # }is inserted at the beginning of the line and after each
new-line, and the line is entered. This causes a comment to be inserted
in the history file. If the line begins with a {\b #}, the {\b #
}is deleted and one {\b # }after each new-line is also deleted.
{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Vi.Editing.Mode} Vi \~Editing \~Mode.
\~\~\~}\par\pard\qc\li840\tx840\tx20000}}There are two typing modes. Initially,
when you enter a command you are in the {\i input }mode. To edit, the user
enters {\i control }mode by typing ESC ({\b 033}) and moves the
cursor to the point needing correction and then inserts or deletes characters
or words as needed. Most control commands accept an optional repeat {\i count
}prior to the command. \par\pard\qc\li840\tx840\tx20000 When in {\b vi }mode on most systems,
canonical processing is initially enabled and the command will be echoed
again if the speed is 1200 baud or greater and it contains any control characters
or less than one second has elapsed since the prompt was printed. The ESC
character terminates canonical processing for the remainder of the command
and the user can then modify the command line. This scheme has the advantages
of canonical processing with the type-ahead echoing of raw mode. \par\pard\qc\li840\tx840\tx20000 If the
option {\b viraw }is also set, the terminal will always have canonical
processing disabled. This mode is implicit for systems that do not support
two alternate end of line delimiters, and may be helpful for certain terminals.
{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Input.Edit.Commands}\~\~\~\~\~ Input
Edit Commands \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}By
default the editor is in input mode. {\i\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 erase }\tab (User defined
erase character as defined by the stty command, usually {\b ^H }or
{\b #}.) Delete previous character. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b ^W }\tab Delete
the previous blank separated word. On some systems the {\b viraw}
option may be required for this to work. {\i\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 eof }\tab As the first character
of the line causes the shell to terminate unless the {\b ignoreeof}
option is set. Otherwise this character is ignored. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b ^V }\tab Escape
next character. Editing characters and the user's erase or kill characters
may be entered in a command line or in a search string if preceded by a
{\b ^V}. The {\b ^V }removes the next character's editing
features (if any). On some systems the {\b viraw} option may be
required for this to work. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b\'5c }\tab Escape the next {\i erase
}or {\i kill }character. {\fs22{\b\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Motion.Edit.Commands}\~\~\~\~\~ Motion
Edit Commands \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}These
commands will move the cursor. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b l}
\tab Cursor forward (right) one character. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b w}
\tab Cursor forward one alpha-numeric word. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b W}
\tab Cursor to the beginning of the next word that follows a blank. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b e}
\tab Cursor to end of word. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b E} \tab Cursor to end
of the current blank delimited word. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b h} \tab Cursor
backward (left) one character. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b b} \tab Cursor
backward one word. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b B} \tab Cursor to preceding
blank separated word. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b |} \tab Cursor to column
{\i count}. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b f}{\i c} \tab Find the next character
{\i c} in the current line. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b F}{\i c} \tab Find
the previous character {\i c} in the current line. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b t}{\i c}
\tab Equivalent to {\b f }followed by {\b h}. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b T}{\i c}
\tab Equivalent to {\b F }followed by {\b l}. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b ;}
\tab Repeats {\i count }times, the last single character find command, {\b f},
{\b F}, {\b t}, or {\b T}. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b ,}
\tab Reverses the last single character find command {\i count }times. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 0
}\tab Cursor to start of line. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 ^ }\tab Cursor to first
non-blank character in line. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 $ }\tab Cursor to end of line.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 % }\tab Moves to balancing {\b (}, {\b )},
{\b\{}, {\b\}}, {\b [}, or {\b ]}. If
cursor is not on one of the above characters, the remainder of the line
is searched for the first occurrence of one of the above characters first.
{\fs22{\b\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Search.Edit.Commands}\~\~\~\~\~ Search
Edit Commands \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}These
commands access your command history. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b k}
\tab Fetch previous command. Each time {\b k }is entered the previous
command back in time is accessed. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b\'2d}
\tab Equivalent to {\b k}. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b j} \tab Fetch
next command. Each time {\b j }is entered the next command forward
in time is accessed. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b +} \tab Equivalent to {\b j}.
\par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b G} \tab The command number {\i count }is fetched.
The default is the least recent history command. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b /}{\i string
}\tab Search backward through history for a previous command containing
{\i string}. {\i String }is terminated by a `RETURN' or `NEW\~LINE'.
If string is preceded by a {\b ^}, the matched line must begin
with {\i string}. If {\i string} is null, the previous string will be
used. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b ?}{\i string }\tab Same as {\b / }except that
search will be in the forward direction. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 n }\tab Search for
next match of the last pattern to {\b / }or {\b ? }commands.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 N }\tab Search for next match of the last pattern to {\b /
}or {\b ?}, but in reverse direction. {\fs22{\b\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Text.Modification.Edit.Commands}\~\~\~\~\~ Text
Modification Edit Commands \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}These
commands will modify the line. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 a }\tab Enter input
mode and enter text after the current character. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 A }\tab Append
text to the end of the line. Equivalent to {\b $a}. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b c}{\i motion}
\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 c}[{\i count}]{\i motion} \tab Delete current character
through the character that {\i motion }would move the cursor to and enter
input mode. If {\i motion} is {\b c}, the entire line will be
deleted and input mode entered. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 C }\tab Delete the current
character through the end of line and enter input mode. Equivalent to {\b c$}.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 S }\tab Equivalent to {\b cc}. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b s}
\tab Replace characters under the cursor in input mode. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 D }\tab Delete
the current character through the end of line. Equivalent to {\b d$}.
\par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b d}{\i motion} \tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 d}[{\i count}]{\i motion}
\tab Delete current character through the character that {\i motion }would
move to. If {\i motion} is {\b d , }the entire line will be deleted.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 i }\tab Enter input mode and insert text before the current
character. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 I }\tab Insert text before the beginning of the
line. Equivalent to {\b 0i}. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b P} \tab Place
the previous text modification before the cursor. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b p}
\tab Place the previous text modification after the cursor. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 R }\tab Enter
input mode and replace characters on the screen with characters you type
overlay fashion. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b r}{\i c} \tab Replace the {\i count
}character(s) starting at the current cursor position with {\i c}, and
advance the cursor. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b x} \tab Delete current character.
\par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b X} \tab Delete preceding character. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b .}
\tab Repeat the previous text modification command. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b ~}
\tab Invert the case of the {\i count }character(s) starting at the current
cursor position and advance the cursor. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b _}
\tab Causes the {\i count }word of the previous command to be appended and
input mode entered. The last word is used if {\i count }is omitted. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 *
}\tab Causes an {\b * }to be appended to the current word and
file name generation attempted. If no match is found, it rings the bell.
Otherwise, the word is replaced by the matching pattern and input mode is
entered. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c }\tab Command or file name completion as described
above. {\fs22{\b\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Other.Edit.Commands}\~\~\~\~\~ Other
Edit Commands \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}Miscellaneous
commands. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b y}{\i motion} \tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 y}[{\i count}]{\i motion}
\tab Yank current character through character that {\i motion }would move
the cursor to and puts them into the delete buffer. The text and cursor
are unchanged. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 yy }\tab Yanks the entire line. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 Y }\tab Yanks
from current position to end of line. Equivalent to {\b y$}. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 u
}\tab Undo the last text modifying command. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 U }\tab Undo
all the text modifying commands performed on the line. \par\pard\qc\fi-560\li1400\tx1400\tx20000 [{\i count}]{\b v}
\tab Returns the command {\b hist \'2de $\{{\fs22 VISUAL}:\'2d$\{{\fs22 EDITOR}:\'2dvi\}\}}{\i
count }in the input buffer. If {\i count }is omitted, then the current
line is used. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b ^L }\tab Line feed and print current line. Has
effect only in control mode. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b ^J }\tab (New\~line) Execute
the current line, regardless of mode. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b ^M }\tab (Return) Execute
the current line, regardless of mode. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 # }\tab If the first
character of the command is a {\b #}, then this command deletes
this {\b # }and each {\b # }that follows a newline. Otherwise,
sends the line after inserting a {\b # }in front of each line in
the command. Useful for causing the current line to be inserted in the history
as a comment and uncommenting previously commented commands in the history
file. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000 = }\tab Command or file name listing as described above.
\par\pard\qc\fi-560\li1400\tx1400\tx20000{\b @}{\i letter }\tab Your alias list is searched for an alias
by the name {\b _}{\i letter }and if an alias of this name is
defined, its value will be inserted on the input queue for processing. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b ^V
}\tab Display version of the shell. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Built.in.Commands} Built-in
\~Commands. \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}The following
simple-commands are executed in the shell process. Input/Output redirection
is permitted. Unless otherwise indicated, the output is written on file
descriptor 1 and the exit status, when there is no syntax error, is zero.
Except for {\b :}, {\b true}, {\b false}, {\b echo},
{\b command}, {\b newgrp}, and {\b login}, all
built-in commands accept {\b\'2d\'2d }to indicate end of
options. They also interpret the option {\b\'2d ? }as a help
request and print a {\i usage }message on standard error. Commands that
are preceded by one or two \'a7 symbols are special built-in commands
and are treated specially in the following ways: \par\pard\qc\fi-560\li1120\tx1120\tx20000 1. \tab Variable
assignment lists preceding the command remain in effect when the command
completes. \par\pard\qc\fi-560\li1120\tx1120\tx20000 2. \tab I/O redirections are processed after variable assignments.
\par\pard\qc\fi-560\li1120\tx1120\tx20000 3. \tab Errors cause a script that contains them to abort. \par\pard\qc\fi-560\li1120\tx1120\tx20000 4. \tab They
are not valid function names. \par\pard\qc\fi-560\li1120\tx1120\tx20000 5. \tab Words following a command preceded
by \'a7\'a7 that are in the format of a variable assignment are
expanded with the same rules as a variable assignment. This means that tilde
substitution is performed after the {\b = }sign and field splitting
and file name generation are not performed. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b :}
[\~{\i arg\~}.\~.\~. \~] \tab The command only expands
parameters. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b\~ . }{\i name\~}{\b [\~}{\i arg\~}{\b .\~.\~.
\~] \tab}If {\i name }is a function defined with the {\b function
}{\i name }reserved word syntax, the function is executed in the
current environment (as if it had been defined with the {\i name}{\b ()
}syntax.) Otherwise if {\i name }refers to a file, the file is read
in its entirety and the commands are executed in the current shell environment.
The search path specified by {\b{\fs22 PATH }}is used to
find the directory containing the file. If any arguments {\i arg }are given,
they become the positional parameters while processing the {\b . }command
and the original positional parameters are restored upon completion. Otherwise
the positional parameters are unchanged. The exit status is the exit status
of the last command executed. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7\'a7 {\b alias} [\~{\b\'2d ptx}
\~] [\~{\i name}[\~{\b =}{\i value\~}\~]\~].\~.\~.
\tab{\b alias }with no arguments prints the list of aliases in the
form {\i name=value }on standard output. The {\b\'2d p }option
causes the word {\b alias }to be inserted before each one. When
one or more arguments are given, an {\i alias }is defined for each {\i name
}whose {\i value }is given. A trailing space in {\i value }causes the
next word to be checked for alias substitution. The obsolete {\b\'2d t
}option is used to set and list tracked aliases. The value of a tracked
alias is the full pathname corresponding to the given {\i name}. The value
becomes undefined when the value of {\fs22{\b PATH }}is
reset but the alias remains tracked. Without the {\b\'2d t }option,
for each {\i name }in the argument list for which no {\i value }is given,
the name and value of the alias is printed. The obsolete {\b\'2d x
}option has no effect. The exit status is non-zero if a {\i name }is
given, but no value, and no alias has been defined for the {\i name\~}.
{\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 bg} [\~{\i job\~}.\~.\~. \~] \tab This
command is only on systems that support job control. Puts each specified
{\i job }into the background. The current job is put in the background
if {\i job }is not specified. See {\i Jobs }for a description of the format
of {\i job}. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b break} [\~{\i n\~}\~]
\tab Exit from the enclosing {\b for\~}, {\b while\~},
{\b until\~}, or {\b select }loop, if any. If {\i n
}is specified, then break {\i n }levels. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 builtin} [\~{\b\'2d ds}
\~] [\~{\b\'2d f} {\i file\~}\~][\~{\i name\~}.\~.\~.\~]
\tab If {\i name }is not specified, and no {\b\'2d f }option
is specified, the built-ins are printed on standard output. The {\b\'2d s
}option prints only the special built-ins. Otherwise, each {\i name
}represents the pathname whose basename is the name of the built-in. The
entry point function name is determined by prepending {\b b_ }to
the built-in name. Special built-ins cannot be bound to a pathname or deleted.
The {\b\'2d d }option deletes each of the given built-ins.
On systems that support dynamic loading, the {\b\'2d f }option
names a shared library containing the code for built-ins. Once a library
is loaded, its symbols become available for subsequent invocations of {\b builtin}.
Multiple libraries can be specified with separate invocations of the {\b builtin
}command. Libraries are searched in the reverse order in which they
are specified. When a library is loaded, it looks for a function in the
library whose name is {\b lib_init() }and invokes this function
with an argument of {\b 0}. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 cd} [\~{\b\'2d LP}
\~] [\~{\i arg\~}\~] \tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 cd} [\~{\b\'2d LP}
\~] {\i old\~}{\i new\~}\tab This command can be in either of
two forms. In the first form it changes the current directory to {\i arg}.
If {\i arg }is {\b\'2d }the directory is changed to the previous
directory. The shell variable {\b{\fs22 HOME }}is the default
{\i arg}. The variable {\fs22{\b PWD }}is set to the current
directory. The shell variable {\b{\fs22 CDPATH }}defines
the search path for the directory containing {\i arg}. Alternative directory
names are separated by a colon ({\b :}). The default path is {\b< null>
}(specifying the current directory). Note that the current directory
is specified by a null path name, which can appear immediately after the
equal sign or between the colon delimiters anywhere else in the path list.
If {\i arg }begins with a {\b /} then the search path is not used.
Otherwise, each directory in the path is searched for {\i arg}. \par\pard\qc\li1120\tx1120\tx20000 The second
form of {\b cd }substitutes the string {\i new }for the string
{\i old }in the current directory name, {\fs22{\b PWD}, }and
tries to change to this new directory. \par\pard\qc\li1120\tx1120\tx20000 By default, symbolic link names
are treated literally when finding the directory name. This is equivalent
to the {\b\'2d L }option. The {\b\'2d P }option
causes symbolic links to be resolved when determining the directory. The
last instance of {\b\'2d L }or {\b\'2d P }on the
command line determines which method is used. \par\pard\qc\li1120\tx1120\tx20000 The {\b cd }command
may not be executed by {\b rsh\~. }{\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 command}
[\~{\b\'2d pvV} \~] {\i name\~}[\~{\i arg\~}.\~.\~.\~]
\tab Without the {\b\'2d v }or {\b\'2d V }options,
{\b command }executes {\i name }with the arguments given by {\i arg}.
The {\b\'2d p }option causes a default path to be searched
rather than the one defined by the value of {\fs22{\b PATH}.
}Functions will not be searched for when finding {\i name}. In addition,
if {\i name }refers to a special built-in, none of the special properties
associated with the leading daggers will be honored. (For example, the predefined
alias {\b redirect='command exec' }prevents a script from terminating
when an invalid redirection is given.) With the {\b\'2d v }option,
{\b command }is equivalent to the built-in {\b whence }command
described below. The {\b\'2d V }option causes {\b command
}to act like {\b whence \'2dv}. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b continue}
[\~{\i n\~}\~] \tab Resume the next iteration of the enclosing
{\b for\~}, {\b while\~}, {\b until\~},
or {\b select }loop. If {\i n }is specified, then resume at the
{\i n}-th enclosing loop. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 disown} [\~{\i job\~}.\~.\~.
\~] \tab Causes the shell not to send a HUP signal to each given {\i job},
or all active jobs if {\i job }is omitted, when a login shell terminates.
{\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 echo} [\~{\i arg\~}.\~.\~. \~] \tab When
the first {\i arg }does not begin with a \'2d, and none of the arguments
contain a \'5c, then {\b echo }prints each of its arguments
separated by a space and terminated by a new-line. Otherwise, the behavior
of {\b echo }is system dependent and {\b print }or {\b printf
}described below should be used. See {\i echo}(1) for usage and description.
\par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b eval} [\~{\i arg\~}.\~.\~. \~]
\tab The arguments are read as input to the shell and the resulting command(s)
executed. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b exec} [\~{\b\'2d c}
\~] [\~{\b\'2d a} {\i name\~}\~][\~{\i arg\~}.\~.\~.\~]
\tab If {\i arg }is given, the command specified by the arguments is executed
in place of this shell without creating a new process. The {\b\'2d c
}option causes the environment to be cleared before applying variable
assignments associated with the {\b exec }invocation. The {\b\'2d a
}option causes {\i name }rather than the first {\i arg}, to become
{\b argv[0] }for the new process. Input/output arguments may appear
and affect the current process. If {\i arg }is not given, the effect of
this command is to modify file descriptors as prescribed by the input/output
redirection list. In this case, any file descriptor numbers greater than
2 that are opened with this mechanism are closed when invoking another program.
\par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b#{\footnote HTML2RTF.exit} exit}[\~{\i n\~}\~] \tab Causes
the shell to exit with the exit status specified by {\i n}. The value will
be the least significant 8 bits of the specified status. If {\i n }is omitted,
then the exit status is that of the last command executed. An end-of-file
will also cause the shell to exit except for a shell which has the {\b ignoreeof
}option (see {\uldb set}{\v HTML2RTF.set}{\*\comment{\b set }}below) turned on. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7\'a7
{\b export} [\~{\b\'2d p} \~] [\~{\i name\~}[\~{\b =}{\i value\~}\~]
\~].\~.\~. \tab If {\i name }is not given, the names and values
of each variable with the export attribute are printed with the values quoted
in a manner that allows them to be re-input. The {\b\'2d p }option
causes the word {\b export }to be inserted before each one. Otherwise,
the given {\i name}s are marked for automatic export to the {\i environment
}of subsequently-executed commands. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 false} \tab Does nothing,
and exits 1. Used with {\b until }for infinite loops. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 fg}
[\~{\i job\~}.\~.\~. \~] \tab This command is only on
systems that support job control. Each {\i job }specified is brought to
the foreground and waited for in the specified order. Otherwise, the current
job is brought into the foreground. See {\i Jobs }for a description of
the format of {\i job}. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 getconf} [\~{\i name\~}[\~{\i pathname\~}\~]
\~] \tab Prints the current value of the configuration parameter given
by {\i name}. The configuration parameters are defined by the IEEE POSIX
1003.1 and IEEE POSIX 1003.2 standards. (See {\i pathconf}(2) and {\i sysconf}(2).)
The {\i pathname }argument is required for parameters whose value depends
on the location in the file system. If no arguments are given, {\b getconf
}prints the names and values of the current configuration parameters.
The pathname {\b / }is used for each of the parameters that requires
{\i pathname}. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 getopts} [\~{\b\~ -a} {\i name\~}\~]
{\i optstring vname\~}[\~{\i arg\~}.\~.\~.\~]
\tab Checks {\i arg }for legal options. If {\i arg }is omitted, the positional
parameters are used. An option argument begins with a {\b + }or
a {\b\'2d}. An option not beginning with {\b + }or
{\b\'2d }or the argument {\b\'2d\~\'2d }ends
the options. {\i optstring }contains the letters that {\b getopts }recognizes.
If a letter is followed by a {\b :}, that option is expected to
have an argument. The options can be separated from the argument by blanks.
The option {\b\'2d ? }causes {\b getopts }to generate
a usage message on standard error. The {\b\'2d a }argument
can be used to specify the name to use for the usage message, which defaults
to {\b $0}. {\b\par\pard\qc\li1120\tx1120\tx20000 getopts }places the next option letter
it finds inside variable {\i vname }each time it is invoked. The option
letter will be prepended with a {\b + }when {\i arg }begins with
a {\b +}. The index of the next {\i arg }is stored in {\fs22{\b OPTIND}.
}The option argument, if any, gets stored in {\fs22{\b OPTARG}.
}\par\pard\qc\li1120\tx1120\tx20000 A leading {\b : }in {\i optstring }causes {\b getopts
}to store the letter of an invalid option in {\fs22{\b OPTARG},
}and to set {\i vname }to {\b ? }for an unknown option and
to {\b : }when a required option is missing. Otherwise, {\b getopts
}prints an error message. The exit status is non-zero when there are
no more options. \par\pard\qc\li1120\tx1120\tx20000 There is no way to specify any of the options {\b :},
{\b +}, {\b\'2d}, {\b ?}, {\b [},
and {\b ]}. The option {\b # }can only be specified as
the first option. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 hist} [\~{\b\'2d e} {\i ename\~}\~\~]
[\~{\b\'2d nlr\~}\~][\~{\i first\~}[\~{\i last\~}\~]\~]
\tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 hist \'2ds }[\~{\i old}{\b =}{\i new\~}\~]
[\~{\i command\~}\~] \tab In the first form, a range of commands
from {\i first }to {\i last }is selected from the last {\fs22{\b HISTSIZE
}}commands that were typed at the terminal. The arguments {\i first
}and {\i last }may be specified as a number or as a string. A string
is used to locate the most recent command starting with the given string.
A negative number is used as an offset to the current command number. If
the {\b\'2d l }option is selected, the commands are listed
on standard output. Otherwise, the editor program {\i ename }is invoked
on a file containing these keyboard commands. If {\i ename }is not supplied,
then the value of the variable {\fs22{\b HISTEDIT }}is
used. If {\fs22{\b HISTEDIT }}is not set, then {\fs22{\b FCEDIT
}}(default {\b /bin/ed\~}) is used as the editor.
When editing is complete, the edited command(s) is executed if the changes
have been saved. If {\i last }is not specified, then it will be set to
{\i first}. If {\i first }is not specified, the default is the previous
command for editing and \'2d16 for listing. The option {\b\'2d r
}reverses the order of the commands and the option {\b\'2d n
}suppresses command numbers when listing. In the second form, {\i command
}is interpreted as {\i first }described above and defaults to the last
command executed. The resulting command is executed after the optional substitution
{\i old\~}{\b =}{\i new\~}is performed. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 jobs}
[\~{\b\'2d lnp\~}\~] [\~{\i job\~}.\~.\~.
\~] \tab Lists information about each given job; or all active jobs if
{\i job }is omitted. The {\b\'2d l }option lists process ids
in addition to the normal information. The {\b\'2d n }option
only displays jobs that have stopped or exited since last notified. The
{\b\'2d p }option causes only the process group to be listed.
See {\i Jobs }for a description of the format of {\i job}. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 kill}
[\~{\b\'2d s} {\i signame\~}\~] {\i job\~}.\~.\~.
\tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 kill} [\~{\b\'2d n} {\i signum\~}\~]
{\i job\~}.\~.\~. \tab{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 kill} {\b\'2d l}
[\~{\i sig\~}.\~.\~. \~] \tab Sends either the TERM (terminate)
signal or the specified signal to the specified jobs or processes. Signals
are either given by number with the {\b\'2d n }option or by
name with the {\b\'2d s }option (as given in {\b< signal.h>},
stripped of the prefix ``SIG'' with the exception that SIGCLD is named CHLD).
For backward compatibility, the {\b n }and {\b s }can
be omitted and the number or name placed immediately after the {\b\'2d}.
If the signal being sent is TERM (terminate) or HUP (hangup), then the job
or process will be sent a CONT (continue) signal if it is stopped. The argument
{\i job }can be the process id of a process that is not a member of one
of the active jobs. See {\i Jobs }for a description of the format of {\i job}.
In the third form, {\b kill \'2dl}, if {\i sig }is not specified,
the signal names are listed. Otherwise, for each {\i sig }that is a name,
the corresponding signal number is listed. For each {\i sig }that is a
number, the signal name corresponding to the least significant 8 bits of
{\i sig }is listed. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 let} {\i arg\~}.\~.\~.
\tab Each {\i arg }is a separate {\i arithmetic expression }to be evaluated.
See {\i Arithmetic Evaluation }above, for a description of arithmetic expression
evaluation. \par\pard\qc\li1120\tx1120\tx20000 The exit status is 0 if the value of the last expression is
non-zero, and 1 otherwise. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b newgrp} [\~{\i arg\~}.\~.\~.
\~] \tab Equivalent to {\b exec /bin/newgrp}{\i arg\~}.\~.\~.\~.
{\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 print} [\~{\b\'2d Rnprs\~}\~] [\~{\b\'2d u}
{\i unit\~}\~] [\~{\b\'2d f}{\i format\~}\~][\~{\i arg\~}.\~.\~.\~]
\tab With no options or with option {\b\'2d }or {\b\'2d\~\'2d},
each {\i arg }is printed on standard output. The {\b\'2d f }option
causes the arguments to be printed as described by {\b printf}.
In this case, any {\b n}, {\b r}, {\b R }options
are ignored. Otherwise, unless the {\b\'2d R }or {\b\'2d r},
are specified, the following escape conventions will be applied: {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c a
}\tab The alert character (ascii {\b 07}). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c b
}\tab The backspace character (ascii {\b 010}). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c c
}\tab Causes {\b print }to end without processing more arguments
and not adding a new-line. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c f }\tab The formfeed character
(ascii {\b 014}). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c n }\tab The new-line character
(ascii {\b 012}). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c r }\tab The carriage return
character (ascii {\b 015}). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c t }\tab The tab
character (ascii {\b 011}). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c v }\tab The vertical
tab character (ascii {\b 013}). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c E }\tab The
escape character (ascii {\b 033}). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'5c\'5c }\tab The
backslash character \'5c. \par\pard\qc\fi-560\li1400\tx1400\tx20000{\b\'5c 0}{\i x }\tab The character
defined by the 1, 2, or 3-digit octal string given by {\i x}. \par\pard\qc\li1120\tx1120\tx20000 The
{\b\'2d R }option will print all subsequent arguments and options
other than {\b\'2d n}. The {\b\'2d p }option causes
the arguments to be written onto the pipe of the process spawned with {\b |&
}instead of standard output. The {\b\'2d s }option causes
the arguments to be written onto the history file instead of standard output.
The {\b\'2d u }option can be used to specify a one digit file
descriptor unit number {\i unit }on which the output will be placed. The
default is 1. If the option {\b\'2d n }is used, no {\b new-line
}is added to the output. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 printf} {\i format\~}[\~{\i arg\~}.\~.\~.
\~] \tab The arguments {\i arg }are printed on standard output in accordance
with the ANSI-C formatting rules associated with the format string {\i format}.
If the number of arguments exceeds the number of format specifications,
the {\b format }string is reused to format remaining arguments.
The following extensions can also be used: \par\pard\qc\li1400\tx1400\tx20000\par\pard\qc\fi-560\li1400\tx1400\tx20000\'b7 \tab A {\b %b
}format can be used instead of {\b %s }to cause escape sequences
in the corresponding {\i arg }to be expanded as described in {\b print.
}\par\pard\qc\li1400\tx1400\tx20000\par\pard\qc\fi-560\li1400\tx1400\tx20000\'b7 \tab A {\b %P }format can be used instead of {\b %s
}to cause {\i arg }to be interpreted as an extended regular expression
and be printed as a shell pattern. \par\pard\qc\li1400\tx1400\tx20000\par\pard\qc\fi-560\li1400\tx1400\tx20000\'b7 \tab A {\b %q }format
can be used instead of {\b %s }to cause the resulting string to
be quoted in a manner than can be reinput to the shell. \par\pard\qc\li1400\tx1400\tx20000\par\pard\qc\fi-560\li1400\tx1400\tx20000\'b7 \tab The
precision field of the {\b %d }format can be followed by a {\b .
}and the output base. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 pwd} [\~{\b\'2d LP}
\~] \tab Outputs the value of the current working directory. The {\b\'2d L
}option is the default; it prints the logical name of the current
directory. If the {\b\'2d P }option is given, all symbolic
links are resolved from the name. The last instance of {\b\'2d L
}or {\b\'2d P }on the command line determines which method
is used. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 read} [\~{\b\'2d Aprs\~}\~]
[\~{\b\'2d d} {\i delim\~}\~] [\~{\b\'2d t}{\i timeout\~}\~][\~{\b\'2d u}{\i unit\~}\~][\~{\i vname}{\b ?}{\i prompt\~}{\b\~ ][\~}{\i vname\~}{\b .\~.\~.\~]
\tab}The shell input mechanism. One line is read and is broken up into
fields using the characters in {\b{\fs22 IFS }}as separators.
The escape character, {\b\'5c}, is used to remove any special
meaning for the next character and for line continuation. The {\b\'2d d
}option causes the read to continue to the first character of {\i delim
}rather than new-line. In raw mode, {\b\'2d r, }the {\b\'5c
}character is not treated specially. The first field is assigned to
the first {\i vname}, the second field to the second {\i vname}, etc.,
with leftover fields assigned to the last {\i vname}. The {\b\'2d A
}option causes the variable {\i vname }to be unset and each field
that is read to be stored in successive elements of the indexed array {\i vname.
}The {\b\'2d p }option causes the input line to be taken
from the input pipe of a process spawned by the shell using {\b |&}.
If the {\b\'2d s }option is present, the input will be saved
as a command in the history file. The option {\b\'2d u }can
be used to specify a one digit file descriptor unit {\i unit }to read from.
The file descriptor can be opened with the {\b exec }special built-in
command. The default value of unit {\i n }is 0. The option {\b\'2d t
}is used to specify a timeout in seconds when reading from a terminal
or pipe. If {\i vname }is omitted, then {\fs22{\b REPLY }}is
used as the default {\i vname}. An end-of-file with the {\b\'2d p
}option causes cleanup for this process so that another can be spawned.
If the first argument contains a {\b ?}, the remainder of this
word is used as a {\i prompt }on standard error when the shell is interactive.
The exit status is 0 unless an end-of-file is encountered or {\b read
}has timed out. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7\'a7 {\b readonly} [\~{\b\'2d p}
\~] [\~{\i vname}[\~{\b =}{\i value\~}\~]
\~].\~.\~. \tab If {\i vname }is not given, the names and values
of each variable with the readonly attribute is printed with the values
quoted in a manner that allows them to be re-inputted. The {\b\'2d p
}option causes the word {\b readonly }to be inserted before
each one. Otherwise, the given {\i vname}s are marked readonly and these
names cannot be changed by subsequent assignment. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b return}
[\~{\i n\~}\~] \tab Causes a shell {\i function }or {\b\~ .}
script to return to the invoking script with the exit status specified by
{\i n}. The value will be the least significant 8 bits of the specified
status. If {\i n }is omitted, then the return status is that of the last
command executed. If {\b return }is invoked while not in a {\i function
}or a {\b\~ .} script, then it behaves the same as {\b exit}.
\par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b#{\footnote HTML2RTF.set} set}[\~{\b\'b1 Cabefhkmnopstuvx}
\~] [\~{\b\'b1 o} [\~{\i option\~}\~]\~].\~.\~.[\~{\b\'b1 A}{\i vname\~}\~][\~{\i arg\~}.\~.\~.\~]
\tab The options for this command have meaning as follows: {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d A
}\tab Array assignment. Unset the variable {\i vname }and assign values
sequentially from the {\i arg }list. If {\b +A }is used, the variable
{\i vname }is not unset first. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d C }\tab Prevents redirection
{\b> }from truncating existing files. Files that are created
are opened with the O_EXCL mode. Requires {\b> | }to truncate
a file when turned on. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d a }\tab All subsequent variables
that are defined are automatically exported. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d b }\tab Prints
job completion messages as soon as a background job changes state rather
than waiting for the next prompt. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d e }\tab If a command
has a non-zero exit status, execute the {\fs22{\b ERR }}trap,
if set, and exit. This mode is disabled while reading profiles. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d f
}\tab Disables file name generation. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d h }\tab Each
command becomes a tracked alias when first encountered. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d k
}\tab (Obsolete). All variable assignment arguments are placed in the
environment for a command, not just those that precede the command name.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d m }\tab Background jobs will run in a separate process
group and a line will print upon completion. The exit status of background
jobs is reported in a completion message. On systems with job control, this
option is turned on automatically for interactive shells. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d n
}\tab Read commands and check them for syntax errors, but do not execute
them. Ignored for interactive shells. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d o }\tab The following
argument can be one of the following option names: {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 allexport
}\tab Same as {\b\'2d a}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 errexit }\tab Same
as {\b\'2d e}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 bgnice }\tab All background jobs
are run at a lower priority. This is the default mode. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 emacs }\tab Puts
you in an {\i emacs }style in-line editor for command entry. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 gmacs
}\tab Puts you in a {\i gmacs }style in-line editor for command entry.
{\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 ignoreeof }\tab The shell will not exit on end-of-file. The
command {\b exit }must be used. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 keyword }\tab Same
as {\b\'2d k}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 markdirs }\tab All directory names
resulting from file name generation have a trailing {\b / }appended.
{\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 monitor }\tab Same as {\b\'2d m}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 noclobber
}\tab Same as {\b\'2d C}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 noexec }\tab Same
as {\b\'2d n}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 noglob }\tab Same as {\b\'2d f}.
{\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 nolog }\tab Do not save function definitions in the history
file. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 notify }\tab Same as {\b\'2d b}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 nounset
}\tab Same as {\b\'2d u}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 privileged }\tab Same
as {\b\'2d p}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 verbose }\tab Same as {\b\'2d v}.
{\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 trackall }\tab Same as {\b\'2d h}. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 vi
}\tab Puts you in insert mode of a {\i vi }style in-line editor until
you hit the escape character {\b 033}. This puts you in control
mode. A return sends the line. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 viraw }\tab Each character is
processed as it is typed in {\i vi }mode. {\b\line\par\pard\qc\fi-560\li1680\tx1680\tx20000 xtrace }\tab Same
as {\b\'2d x}. \par\pard\qc\fi-560\li1680\tx1680\tx20000 If no option name is supplied, then thecurrentoptionsettingsareprinted.
\tab{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d p }\tab Disables processing of the {\b{\fs22 $HOME}/.profile
}file and uses the file {\b /etc/suid_profile }instead of
the {\fs22{\b ENV }}file. This mode is on whenever the
effective uid (gid) is not equal to the real uid (gid). Turning this off
causes the effective uid and gid to be set to the real uid and gid. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d s
}\tab Sort the positional parameters lexicographically. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d t
}\tab (Obsolete). Exit after reading and executing one command. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d u
}\tab Treat unset parameters as an error when substituting. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d v
}\tab Print shell input lines as they are read. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d x }\tab Print
commands and their arguments as they are executed. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d\~\'2d
}\tab Do not change any of the options; useful in setting {\b $1
}to a value beginning with {\b\'2d}. If no arguments
follow this option then the positional parameters are unset. \par\pard\qc\li1120\tx1120\tx20000 As an
obsolete feature, if the first {\i arg }is {\b\'2d }then the
{\b\'2d x }and {\b\'2d v }options are turned off
and the next {\i arg }is treated as the first argument. Using {\b +
}rather than {\b\'2d }causes these options to be turned
off. These options can also be used upon invocation of the shell. The current
set of options may be found in {\b $\'2d}. Unless {\b\'2d A
}is specified, the remaining arguments are positional parameters and
are assigned, in order, to {\b $1 }{\b $2 }.\~.\~.\~.
If no arguments are given, then the names and values of all variables are
printed on the standard output. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b shift} [\~{\i n\~}\~]
\tab The positional parameters from {\b $}{\i n}{\b +1}
.\~.\~. are renamed {\b $1 }.\~.\~.\~, default
{\i n }is 1. The parameter {\i n }can be any arithmetic expression that
evaluates to a non-negative number less than or equal to {\b $#}.
{\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 sleep} {\i seconds\~}\tab Suspends execution for the
number of decimal seconds or fractions of a second given by {\i seconds}.
\par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b trap'} [\~{\b\'2d p} \~] [\~{\i action\~}\~][\~{\i sig\~}\~].\~.\~.
\tab The {\b\'2d p }option causes the trap action associated
with each trap as specified by the arguments to be printed with appropriate
quoting. Otherwise, {\i action }will be processed as if it were an argument
to {\b eval }when the shell receives signal(s) {\i sig}. Each
{\i sig }can be given as a number or as the name of the signal. Trap commands
are executed in order of signal number. Any attempt to set a trap on a signal
that was ignored on entry to the current shell is ineffective. If {\i action
}is omitted and the first {\i sig }is a number, or if {\i action }is
{\b\'2d}, then the trap(s) for each {\i sig }are reset to
their original values. If {\i action }is the null string then this signal
is ignored by the shell and by the commands it invokes. If {\i sig }is
{\fs22{\b ERR }}then {\i action }will be executed whenever
a command has a non-zero exit status. If {\i sig }is {\fs22{\b DEBUG
}}then {\i action }will be executed before each command. If {\i sig
}is {\b 0 }or {\fs22{\b EXIT }}and the {\b trap
}statement is executed inside the body of a function, then the command
{\i action }is executed after the function completes. If {\i sig }is {\b 0
}or {\fs22{\b EXIT }}for a {\b trap }set
outside any function then the command {\i action }is executed on exit from
the shell. If {\i sig }is {\fs22{\b KEYBD}, }then {\i action
}will be executed whenever a key is read while in {\b emacs},
{\b gmacs}, or {\b vi }mode. The {\b trap }command
with no arguments prints a list of commands associated with each signal
number. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 true} \tab Does nothing, and exits 0. Used with {\b while
}for infinite loops. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7\'a7 {\b typeset} [\~{\b\'b1 AHflnprtux\~}\~]
[\~{\b\'b1 EFLRZi[\~}{\i n\~}{\b\~ ] \~][\~}{\i vname\~}{\b [\~=}{\i value\~}{\b\~ ]\~\~].\~.\~.
\tab}Sets attributes and values for shell variables and functions. When
invoked inside a function, a new instance of the variable {\i vname }is
created. The variable's value and type are restored when the function completes.
The following list of attributes may be specified: {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d A
}\tab Declares {\i vname }to be an associative array. Subscripts are
strings rather than arithmetic expressions. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d E }\tab Declares
{\i vname }to be a double precision floating point number. If {\i n }is
non-zero, it defines the number of significant figures that are used when
expanding {\i vname}. Otherwise, ten significant figures will be used.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d F }\tab Declares {\i vname }to be a double precision
floating point number. If {\i n }is non-zero, it defines the number of
places after the decimal point that are used when expanding {\i vname}.
Otherwise ten places after the decimal point will be used. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d H
}\tab This option provides UNIX to host-name file mapping on non-UNIX
machines. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d L }\tab Left justify and remove leading blanks
from {\i value}. If {\i n }is non-zero, it defines the width of the field,
otherwise it is determined by the width of the value of first assignment.
When the variable is assigned to, it is filled on the right with blanks
or truncated, if necessary, to fit into the field. The {\b\'2d R
}option is turned off. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d R }\tab Right justify
and fill with leading blanks. If {\i n }is non-zero, it defines the width
of the field, otherwise it is determined by the width of the value of first
assignment. The field is left filled with blanks or truncated from the end
if the variable is reassigned. The {\b\'2d L }option is turned
off. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d Z }\tab Right justify and fill with leading zeros
if the first non-blank character is a digit and the {\b\'2d L }option
has not been set. Remove leading zeros if the {\b\'2d L }option
is also set. If {\i n }is non-zero, it defines the width of the field,
otherwise it is determined by the width of the value of first assignment.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d f }\tab The names refer to function names rather than
variable names. No assignments can be made and the only other valid options
are {\b\'2d t}, {\b\'2d u }and {\b\'2d x}.
The {\b\'2d t }option turns on execution tracing for this function.
The {\b\'2d u }option causes this function to be marked undefined.
The {\fs22{\b FPATH }}variable will be searched to find
the function definition when the function is referenced. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d i
}\tab Declares {\i vname }to be represented internally as integer.
The right hand side of an assignment is evaluated as an arithmetic expression
when assigning to an integer. If {\i n }is non-zero, it defines the output
arithmetic base, otherwise the output base will be ten. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d l
}\tab All upper-case characters are converted to lower-case. The upper-case
option, {\b\'2d u}, is turned off. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d n }\tab Declares
{\i vname }to be a reference to the variable whose name is defined by the
value of variable {\i vname}. This is usually used to reference a variable
inside a function whose name has been passed as an argument. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d r
}\tab The given {\i vname}s are marked readonly and these names cannot
be changed by subsequent assignment. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d t }\tab Tags the
variables. Tags are user definable and have no special meaning to the shell.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d u }\tab All lower-case characters are converted to
upper-case. The lower-case option, {\b\'2d l}, is turned off.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d x }\tab The given {\i vname}s are marked for automatic
export to the {\i environment }of subsequently-executed commands. Variables
whose names contain a {\b{\fs26 .}} cannot be exported.
\par\pard\qc\li1120\tx1120\tx20000 The {\b\'2d i }attribute cannot be specified along with
{\b\'2d R}, {\b\'2d L}, {\b\'2d Z},
or {\b\'2d f}. \par\pard\qc\li1120\tx1120\tx20000 Using {\b + }rather than {\b\'2d
}causes these options to be turned off. If no {\i vname }arguments
are given, a list of {\i vnames }(and optionally the {\i values\~})
of the {\i variables }is printed. (Using {\b + }rather than {\b\'2d
}keeps the values from being printed.) The {\b\'2d p }option
causes {\b typeset }followed by the option letters to be printed
before each name rather than the names of the options. If any option other
than {\b\'2d p }is given, only those variables which have all
of the given options are printed. Otherwise, the {\i vname}s and {\i attributes
}of all {\i variables }are printed. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 ulimit} [\~{\b\'2d HSacdfmnpstv}
\~] [\~{\i limit\~}\~] \tab Set or display a resource limit.
The available resource limits are listed below. Many systems do not support
one or more of these limits. The limit for a specified resource is set when
{\i limit }is specified. The value of {\i limit }can be a number in the
unit specified below with each resource, or the value {\b unlimited}.
The {\b\'2d H }and {\b\'2d S }options specify
whether the hard limit or the soft limit for the given resource is set.
A hard limit cannot be increased once it is set. A soft limit can be increased
up to the value of the hard limit. If neither the {\b H }nor {\b S
}options is specified, the limit applies to both. The current resource
limit is printed when {\i limit }is omitted. In this case, the soft limit
is printed unless {\b H }is specified. When more than one resource
is specified, then the limit name and unit is printed before the value.
{\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d a }\tab Lists all of the current resource
limits. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d c }\tab The number of 512-byte blocks on the
size of core dumps. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d d }\tab The number of K-bytes on
the size of the data area. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d f }\tab The number of 512-byte
blocks on files that can be written by the current process or by child processes
(files of any size may be read). {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d m }\tab The number
of K-bytes on the size of physical memory. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d n }\tab The
number of file descriptors plus 1. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d p }\tab The number
of 512-byte blocks for pipe buffering. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d s }\tab The
number of K-bytes on the size of the stack area. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d t }\tab The
number of CPU seconds to be used by each process. {\b\line\par\pard\qc\fi-560\li1400\tx1400\tx20000\'2d v }\tab The
number of K-bytes for virtual memory. \par\pard\qc\li1120\tx1120\tx20000 If no option is given, {\b\'2d f
}is assumed. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 umask} [\~{\b\'2d S}
\~] [\~{\i mask\~}\~] \tab The user file-creation mask is
set to {\i mask }(see {\i umask}(2)). {\i mask }can either
be an octal number or a symbolic value as described in {\i chmod}(1). If
a symbolic value is given, the new umask value is the complement of the
result of applying {\i mask }to the complement of the previous umask value.
If {\i mask }is omitted, the current value of the mask is printed. The
{\b\'2d S }option causes the mode to be printed as a symbolic
value. Otherwise, the mask is printed in octal. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7 {\b unalias}
[\~{\b\'2d a} \~] {\i name\~}.\~.\~. \tab The
aliases given by the list of {\i name}s are removed from the alias list.
The {\b\'2d a }option causes all the aliases to be unset. \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000\'a7{\b unset}
[\~{\b\'2d fnv} \~] {\i vname\~}.\~.\~.
\tab The variables given by the list of {\i vname}s are unassigned, i.e.,
their values and attributes are erased. Readonly variables cannot be unset.
If the {\b\'2d f }option is set, then the names refer to {\i function
}names. If the {\b\'2d v }option is set, then the names refer
to {\i variable }names. The {\b\'2d f }option overrides {\b\'2d v}.
If {\b\'2d n }is set and {\i name }is a name reference, then
{\i name }will be unset rather than the variable that it references. The
default is equivalent to {\b\'2d v}. Unsetting {\fs22{\b LINENO},
}{\fs22{\b MAILCHECK}, }{\fs22{\b OPTARG},
}{\fs22{\b OPTIND}, }{\fs22{\b RANDOM},
}{\fs22{\b SECONDS}, }{\fs22{\b TMOUT},
}and {\fs22{\b _ }}removes their special meaning even
if they are subsequently assigned to. {\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 wait} [\~{\i job\~}.\~.\~.
\~] \tab Wait for the specified {\i job }and report its termination status.
If {\i job }is not given, then all currently active child processes are
waited for. The exit status from this command is that of the last process
waited for. See {\i Jobs }for a description of the format of {\i job}.
{\b\par\pard\qc\li1120\tx1120\tx20000\line\par\pard\qc\fi-560\li1120\tx1120\tx20000 whence} [\~{\b\'2d afpv} \~] {\i name\~}.\~.\~.
\tab For each {\i name}, indicate how it would be interpreted if used as
a command name. \par\pard\qc\li1120\tx1120\tx20000 The {\b\'2d v }option produces a more verbose
report. The {\b\'2d f }options skips the search for functions.
The {\b\'2d p }option does a path search for {\i name }even
if name is an alias, a function, or a reserved word. The {\b\'2d a
}option is similar to the {\b\'2d v }option but causes
all interpretations of the given name to be reported. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Invocation} Invocation.
\~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}If the shell is invoked
by {\i exec}(2), and the first character of argument zero ({\b $0})
is {\b\'2d}, then the shell is assumed to be a {\i login }shell
and commands are read from {\b /etc/profile }and then from either
{\b .profile }in the current directory or {\b{\fs22 $HOME}/.profile},
if either file exists. Next, for interactive shells, commands are read from
the file named by performing parameter expansion, command substitution,
and arithmetic substitution on the value of the environment variable {\fs22{\b ENV
}}if the file exists. If the {\b\'2d s }option is
not present and {\i arg }is, then a path search is performed on the first
{\i arg }to determine the name of the script to execute. The script {\i arg
}must have read permission and any {\i setuid }and {\i setgid }settings
will be ignored. If the script is not found on the path, {\i arg }is processed
as if it named a built-in command or function. Commands are then read as
described below; the following options are interpreted by the shell when
it is invoked: \par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b\'2d c }\tab If the {\b\'2d c
}option is present, then commands are read from the first {\i arg}.
Any remaining arguments become positional parameters starting at {\b 0}.
{\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d s }\tab If the {\b\'2d s }option is present
or if no arguments remain, then commands are read from the standard input.
Shell output, except for the output of the {\i special builtin-in commands
}listed above, is written to file descriptor 2. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d i }\tab If
the {\b\'2d i }option is present or if the shell input and
output are attached to a terminal (as told by {\i tcgetattr}(2)), then
this shell is {\i interactive}. In this case {\fs22 TERM} is ignored
(so that {\b kill 0} does not kill an interactive shell) and {\fs22 INTR}
is caught and ignored (so that {\b wait }is interruptible). In
all cases, {\fs22 QUIT} is ignored by the shell. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d r
}\tab If the {\b\'2d r }option is present, the shell is
a restricted shell. {\b\line\par\pard\qc\fi-560\li1120\tx1120\tx20000\'2d D }\tab A list of all double quoted
strings that are preceded by a {\b $ }will be printed on standard
output and the shell will exit. This set of strings will be subject to language
translation when the locale is not C or POSIX. No commands will be executed.
\par\pard\qc\li1120\tx1120\tx20000\par\pard\qc\fi-560\li1120\tx1120\tx20000{\b\'2d I}{\i filename\~}\tab The {\b\'2d R }{\i filename
}option is used to generate a cross reference database that can be used
by a separate utility to find definitions and references for variables and
commands. \par\pard\qc\li840\tx840\tx20000 The remaining options and arguments are described under the
{\b set }command above. An optional {\b\'2d }as the
first argument is ignored. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.Rsh.Only} Rsh \~Only.
\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}{\i Rsh }is used to set up login
names and execution environments whose capabilities are more controlled
than those of the standard shell. The actions of {\b rsh }are identical
to those of {\b sh\~}, except that the following are disallowed:
\line changing directory (see {\i cd}(1)), \line setting
or unsetting the value or attributes of {\fs22{\b SHELL}, }{\fs22{\b ENV},
}or {\fs22{\b PATH}}{\fs20 0, }\line specifying
path or command names containing {\b /}, \line redirecting output
({\b>}, {\b> |}, {\b<>}, and {\b>>}).
\line adding or deleting built-in commands. \par\pard\qc\li840\tx840\tx20000 The restrictions above are
enforced after {\b .profile} and the {\fs22{\b ENV }}files
are interpreted. \par\pard\qc\li840\tx840\tx20000 When a command to be executed is found to be a shell
procedure, {\b rsh }invokes {\i sh\~}to execute it. Thus,
it is possible to provide to the end-user shell procedures that have access
to the full power of the standard shell, while imposing a limited menu of
commands; this scheme assumes that the end-user does not have write and
execute permissions in the same directory. \par\pard\qc\li840\tx840\tx20000 The net effect of these rules
is that the writer of the {\b .profile }has complete control over
user actions, by performing guaranteed setup actions and leaving the user
in an appropriate directory (probably {\i not }the login directory). \par\pard\qc\li840\tx840\tx20000 The
system administrator often sets up a directory of commands (e.g., {\b /usr/rbin})
that can be safely invoked by {\b rsh}. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.EXIT.STATUS} EXIT
\~STATUS \~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}Errors detected
by the shell, such as syntax errors, cause the shell to return a non-zero
exit status. Otherwise, the shell returns the exit status of the last command
executed (see also the {\uldb exit}{\v HTML2RTF.exit}{\*\comment{\b exit }}command above). If
the shell is being used non-interactively, then execution of the shell file
is abandoned. Run time errors detected by the shell are reported by printing
the command or function name and the error condition. If the line number
that the error occurred on is greater than one, then the line number is
also printed in square brackets ({\b []}) after the command or
function name. {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.FILES} FILES \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}/etc/passwd
\line /etc/profile \line /etc/suid_profile {\fs22\line $HOME}/{\b .}profile
\line /tmp/sh* \line /dev/null {\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.SEE.ALSO} SEE \~ALSO
\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}cat(1), cd(1), chmod(1), cut(1),
echo(1), emacs(1), env(1), gmacs(1), newgrp(1), stty(1), test(1), umask(1),
vi(1), dup(2), exec(2), fork(2), ioctl(2), lseek(2), paste(1), pathconf(2),
pipe(2), sysconf(2), umask(2), ulimit(2), wait(2), rand(3), a.out(5), profile(5),
environ(7). \par\pard\qc\li840\tx840\tx20000 Morris I. Bolsky and David G. Korn, {\i The New KornShell Command
and Programming Language}, Prentice Hall, 1995. {\i\par\pard\qc\li840\tx840\tx20000 POSIX \'2d Part
2: Shell and Utilities, }IEEE Std 1003.2-1992, ISO/IEC 9945-2, IEEE, 1993.
{\fs22{\b\par\pard\qc\li840\tx840\tx20000\line\par\pard\qc\fi-560\li840\tx840\tx20000{\b\fs30#{\footnote HTML2RTF.CAVEATS} CAVEATS \~\~\~\~\~}\par\pard\qc\li840\tx840\tx20000}}If
a command is executed, and then a command with the same name is installed
in a directory in the search path before the directory where the original
command was found, the shell will continue to {\i exec }the original command.
Use the {\b\'2d t }option of the {\b alias }command
to correct this situation. \par\pard\qc\li840\tx840\tx20000 Some very old shell scripts contain a {\b ^
}as a synonym for the pipe character {\b |}. \par\pard\qc\li840\tx840\tx20000 Using the
{\b hist }built-in command within a compound command will cause
the whole command to disappear from the history file. \par\pard\qc\li840\tx840\tx20000 The built-in command
{\b\~ .} {\i file\~}reads the whole file before any commands
are executed. Therefore, {\b alias }and {\b unalias }commands
in the file will not apply to any commands defined in the file. \par\pard\qc\li840\tx840\tx20000 Traps
are not processed while a job is waiting for a foreground process. Thus,
a trap on {\b CHLD }won't be executed until the foreground job
terminates. \par\pard\qc\li840\tx840\tx20000 It is a good idea to leave a space after the comma operator
in arithmetic expressions to prevent the comma from being interpreted as
the decimal point character in certain locales. {\brdrt\brdrsh\par}{\b\fs32\par\pard\qc\li0\tx0\tx20000\~ Sun
Release 4.0\~\~\~\~\~\~\~\~\~\~\~\~\~Last change:\~\~\~\~\~\~\~\~\~\~\~\~1b}
}
}
