- find
1. Find and replace text in all files matching certain name scheme
find . -iname "*.py" -type f -exec sed -i '' 's/abc/XYZ/gi' {} \;
2. One line summary of files
find . -exec file {} +
- "+" Adds the executed command to the same line with spacing
- "\;" Terminates command (escapes semicolon)
3. Find just the subdirectory name in *preqs/pkg/*" with modified time 10 days ago
find . -maxdepth 3 -type d -path "*preqs/pkg/*" -mtime +10
4. Find hardlinks for the same file
find . -samefile /path/to/file
- du
1. Find disk used in human-readable output with a total count of max-depth 1
du -hc --max-depth=1
- bc
1. Converting numbers between bases using 'bc'
echo "obase=2; ibase=16; C497" | bc
- Changing MAC address:
sudo ifconfig en0 ether 00:e1:e2:e3:e4:e5
(last argument is an example MAC address)
1. Generate a random one:
openssl rand -hex 6 | sed 's/\(..\)/\1:/g; s/.$//'
- Finding public IP Address
curl ipinfo.io/ip
- YARD
1. Generate document:
yardoc <filename>
2. Run server [hot-reload]
yard server [-r]
- gpg
1. Generate key pair
gpg --full-generate-key
1. List keys
gpg -k (public)
gpg -K (secret)
2. Export a public key
- Get the ID via 'gpg -k'
gpg -e <public key ID>
3. Import (someone else's) public key
gpg --import <file.asc>
4. Sign a key
gpg --edit-key <key ID or email address>
sign
save
5. Verify a key (if necessary)
- Grab the fingerprint of their key and ask them to do the same
gpg --fingerprint <[email protected]>
6. Encrypt a file (requires recipient's public key)
gpg -e -a -r <recipient> -o <output_file> <file>
- 'e': encrypt
- 'a': armor (textual encoding instead of binary)
7. Decrypt a file (requires your passphrase)
gpg -d -o <new_file> <file>
8. Export/Import a private key
gpg --export-secret-keys <$ID> > my-private-key.asc
gpg --import my-private-key.asc
9. Get key ID (it is on the same line as pub/sec)
gpg -K --keyid-format LONG
10. Renew expired key
gpg --edit-key <[email protected]>
key [1, 2]
expire
- dig
1. For CNAME or A record lookup
dig <A/CNAME> <URL>
- awk
1. String pattern matching and interaction
2. Signature: awk 'pattern { action }' [file] (if not given, uses STDIN
ls | awk '/li/ { print $0 }'
3. Substitute within string
ls | awk '/li/ {gsub(/ /, ""); print $1}'
- tmux
1. Prefix is <C-a>
2. Detach: <prefix> + d
3. New window: <prefix> + c (C to name)
4. Close pane: <prefix> + x
5. Copy mode:
- Enter: <prefix> + [
- Use vim keys to do highlighting, then 'y' to copy
- Paste: <prefix> + ]
6. Renaming (inside tmux):
- Session: <prefix> + $
- Window: <prefix> + ,
7. Navigating windows:
- <prefix> + p (or) n
- Search by text: <prefix> + f
- List of current windows: <prefix> + w
8. Send keys to all panes (toggle on/off): <prefix> + <C-b>
9. Change window number: <prefix> + .
10. Resizing panes:
- Resize panes equally: <prefix> + <space>
- Resize pane some other way:
- <prefix> + :
- 'resize-pane -{D, U, L, R} [#]'
- Interactively
- Hold down <prefix> + up, down, left, right arrows
11. Re-arrange panes:
- <prefix> + { or }
- additionally, you can use command ':swap-pane -{D, U, L, R}'
12. Move a window as a pane in an another window
- <prefix> + :
- 'join-pane -t <destination_window_number>'
13. Break the pane into a window
- <prefix> + !
14. Swap windows
- <prefix> + :
- 'swap-window -s {number of source window} -t {number of target}'
15. Change pane layout
- <prefix> + <space>
- nmap
1. Scan network for open SSH
nmap -sS -p 22 192.168.1.0/24
- "-sS": SYN scan, only wait for response
- "-p 22": Search port 22 (SSH)
- "/24": Refers to how many bits are used up in address space. Since IP4
addresses are of length 32 bits, 32 - 24 = 8 bits or 256. This leaves the
last 0-255 to be scanned.
2. Scan network for available hosts (do not do port scanning)
nmap -sP "192.168.0.*" (or 192.168.0.0/24)
- vim
1. Copying filenames and directories (leader mappings)
- cfr (relative path + file)
- cfa (absolute path + file)
- cff (filename only)
- cfd (directory name)
2. INSERT mode
- <CTRL-w> Deletes back one word
- <CTRL-u> Deletes back entire line
3. Execute macro on multiple lines
- Use Ex mode:
- :5,10norm! @q
- Or visually select lines, then
- :norm! @q
4. Resize splits:
- <CTRL-w> +/- increase/decrease height
- <CTRL-w> >/< increase/decrease width
- <CTRL-w>_ set height (max with no count) (50<C-w>_)
- <CTRL-w>| set width (max with no count) (50<C-w>|)
- <CTRL-w>= resize equally
5. Count matches
- :%s/pattern//ng (n flag counts matches)
6. Print all lines matching pattern
- :g/pattern
7. Increment numbers in a sequence (after visual selection)
- g<CTRL-a>
- vim-sexp-mappings(-for regular people)
"Form": Anything surrounded by a pair of (), [], or {}
"Element": Pretty much anything else
1. "<I" and ">I" for insertion at beginning and end of form
2. Slurp and barf -- ex. ((a |b) c d) -> ((a b c) d):
- ">)" or "<)" or ">(" or "<("
- angle bracket indicates direction, parenthesis indicates which end to
operate on
3. Move a form or element: ">f" or "<f", ">e" or "<e"
4. With surround.vim: use "f" or "e"
- fzf (in vim)
1. :Commits
- Git commits
2. :Lines
- easy_align (vim)
1. visually select group, press "ga"
- delimiters: (<Space>, =, :, ., |, &, #, ",")
- regex: <ctrl+x> in interactive mode
---
= Around the 1st occurrences
2= Around the 2nd occurrences
*= Around all occurrences
**= Left/Right alternating alignment around all occurrences
<Enter> Switching between left/right/center alignment modes
---
2. Set ignore groups: <Ctrl-g> (default: string, comment)
3. :LiveEasyAlign for preview (press same delim to finalize)
- docker
1. Grab an image
docker pull <image>
2. Run a container from an image
docker run <image>
- flags: -it (an interactive tty session)
- flag: --rm (automaticaly delete the container once exited, good for one-offs)
- flag: -d (detached mode)
- flag: -P (publish all exposed ports to random ports)
- flag: -p <port:80> (specify a custom port)
- flag: --name (names the container)
3. List all containers (running or stopped)
docker ps -a
4. List all images
docker images
5. See the ports
docker port <container>
6. Remove a docker container
docker rm <container_id>
- Can also add $(docker ps -a -q -f status=exited) to list only the
container_ids for batch removal of exited containers
- OR:
docker container prune
7. Remove an image
docker rmi <image_id>
- ssh
1. Login:
ssh <username>@<IP address>
If you want to change your password:
- passwd
2. Create an SSH key:
(As per https://blog.g3rt.nl/upgrade-your-ssh-keys.html)
~/.ssh
ssh-keygen -o -a 100 -t ed25519 -f id_<filename> -C "<comment>"
(Make sure to create a passphrase)
3. Add it to remote authorized_keys, grab the *.pub version:
cat id_ed.pub | pbcopy
ssh <username>@<IP address>
cd ~/.ssh/authorized_keys -> vim -> paste in id_ed.pub contents
(alternatively use ssh-add)
4. Login using the key:
ssh -i <path to private SSH key> <username>@<IP address>
5. Do not attempt key-based auth first, if you get too many auth key failures set:
ssh -o "PubkeyAuthentication=no" <username>@<IP Address>
6. If you still get asked for a password, use option:
-o "IdentitiesOnly=yes"
7. Get fingerprint (md5)
ssh-keygen -E md5 -lf <path-to-ssh-key>
8. Tunneling (-N: do not execute remote commands, -T: disable pty allocation)
ssh -L [local_address]:<port>:<remote_address>:<remote_port> -N -T <machine>
example: ssh -i <id_file> -L localhost:8088:localhost:8082 -N -T [email protected]
- usermod
(Add a user "sudo" privileges, check 'visudo' for the %sudo group)
usermod -aG admin <user>
- rails (console)
1. Fuzzy/wildcard search on model
Model.where('name ILIKE ?', '%word%')
- git
1. Add deleted files to staging
git add -u
2. Show current commit hash
git rev-parse [--short] HEAD
3. Revert a file to a certain commit/branch name
git checkout [commit sha/branch name] -- <filename1> [filename2...n]
4. Diff a file to a certain time
git diff <commit sha> <filename>
- netcat
1. Send a file on the same network
=> Receiver:
nc -l 8080 > file
=> Sender:
cat file | nc <RECV_IP> 8080
2. Send a file over the internet
=> Receiver:
nc -l <PORT> | tar xvfz -
=> Sender:
tar cfz - <file> | nc <RECV_IP> <PORT>
3. Checking if a specific port is connectable
nc -z <HOSTNAME> <PORT>
- netstat
1. Find listening network connections (use -t for TCP, -u for UDP)
netstat -l -t
2. Find the program/PID associated with the connection
netstat -p
- apt
1. List installed packages
apt list --installed
2. Get information about possible problems
apt-listchanges <package> (shows info in /usr/share/doc/<package>/NEWS.Debian)
- apt-cache
1. Get Installed and Candidate versions
apt-cache policy <package>
2. Get Depends header
apt-cache depends <package>
3. Get unmet dependencies
apt-cache unmet <package>
- Pi monitoring
1. nethogs
2. htop
3. goaccess
-> generate html report via:
sudo zcat access.log.* | goaccess -a -o report.html
- ctags
1. Respect .gitignore file
ag -l | ctags -R --links=no -L -
- od
1. Use to get a octal/ASCII dump of something
(-An: address none, -tuC: type unsigned integer of size one char)
echo -n Apple | od -An -tuC
- go
1. Debugger
dlv debug <main.go> -- (options) -- (command-line args)
2. Inside delve, set breakpoint to main, then wherever else
break main
list
continue
3. pprof, add either CPU profile or heap profile:
```
// For cpu profile, put this at the beginning of the program
f, _ := os.Create("cpu.out") // or "mem.out"
pprof.StartCPUProfile(f)
defer pprof.StartCPUProfile()
// for heap profile, put this at the end of the program
pprof.WriteHeapProfile(f)
```
go tool pprof -alloc_space m.out # for heap/memory allocation
go tool pprof cpu.out # for cpu
- irssi
1. Scroll up and down
fn + Up/Down (page up/down)
2. Config
https://git.sr.ht/~aos/irssi
3. Switch servers (without disconnecting)
Ctrl-x
- desktop notifications (mac osx)
1. Using AppleScript: display notification "Hello there" with title "Yes"
osascript -e 'display notification "Hello there" with title "Yes"'
- jq
1. Preview using fzf
echo '' | fzf --print-query --preview-window wrap --preview 'cat <JSON>.json | jq {q}'
- sed
1. Edit files in place
sed -i '' 's/blah/toBlah/g' (macOSX)
sed -i 's/blah/blahAgain/g'
2. run multiple commands using -e
sed -i -e 's/edit/intothis/g' -e 's/butAlso/Thishere/g'
3. Append lines after match (use /a)
sed -e '/thisMatch/a "Add this line below thisMatch"'
- nightlight
gsettings set org.gnome.settings-daemon.plugins.color night-light-temperature <TEMP>
- psql (from the shell) -- bring up help with `\?`
1. Connect to a psql shell
psql -U <username> -h <hostname> [< <pipe in .sql file to run query>]
2. List databases
\l
3. List tables
\dt
4. Describe table (see how it's structured)
\d <table name>
5. List schemas
\dn
6. See what the command is doing behind the scenes
EXPLAIN <COMMAND>
-> Ex: EXPLAIN SELECT * FROM rides;
-- Timescale DB funcs:
time_bucket('5 minutes', <time_column>)
- i3
1. Switch to stacked layout
$mod + s
2. Run something
$mod + d
3. Toggle full screen
$mod + f
- lsof
1. Show processes that are using a particular port
lsof -i tcp:<port number>
- dpkg
1. List files installed by package
dpkg -L <package-name>
2. Print architecture
dpkg --print-architecture
3. Check status of package
dpkg -s <package-name>
4. Find the package which contains file
dpkg -S <file-name>
5. List packages known
dpkg -l '[optional search]'
6. List files of specified debian package (.deb)
dpkg -c <filename>.deb
7. Display headers of package (.deb)
dpkg -I <filename>.deb
8. Get list of installed packages
dpkg --get-selections
- dpkg-deb (work with ".deb" files)
1. Extract package
dpkg-deb -X <deb> <directory>
- socat
1. Create a VPN connection to a server through ssh, using TUN
- This allows us to reach 192.168.32.1 and don't need to specify or forward
certain ports
socat -d -d TUN:192.168.32.2/24,up \
SYSTEM:"ssh root@server socat -d -d - 'TUN:192.168.32.1/24,up'"
- mtpaint / gthumb
1. For cropping: gthumb
2. For drawing shapes: mtpaint
