_2d

#
# 2d  [ - | + ] | [ cmd ... ]
#
# @(#)2d (AT&T Bell Laboratories) 06/22/93
#
#	2d	start 2d shell
#	2d -	disable 2d [ enable 3d ]
#	2d +	enable 2d [ disable 3d ]
#	2d cmd	run cmd in 2d
#

function _2d
{
	option=$(vpath /#option/3d 2>/dev/null)
	case $option in
	?*)	trap "set +o noglob; vpath \$option; export LD_PRELOAD='$LD_PRELOAD' _RLD_LIST='$_RLD_LIST' _RLDN32_LIST='$_RLDN32_LIST'" 0 INT QUIT
		vpath - /#option/2d
		;;
	esac
	set +o noglob
	if	test -d .
	then	case $1 in
		-|+)	case $1 in
			+)	option="- /#option/2d" ;;
			-)	option="- /#option/3d" ;;
			esac
			return
			;;
		esac
		# this is close: ^A can't appear in $@
		typeset IFS='
'
		unset __ LD_PRELOAD _RLD_LIST
		case $1 in
		[-+]*)	$SHELL $@ ;;
		*)	${@-$SHELL} ;;
		esac
	else	print -u2 . not found
		return 1
	fi
}