Panel Functions

Common Functions

Shell functions

Useful settings

Here is my configuration (press F9 to navigate the menu):

File actions

• Menu > Command > Edit extension file
• set mpv for video files
• set geeqie for images
• set mcomix for cbz/cbr

Source: Klimer, MC HP, Kayxl, ArchLinux forum

Window managers

• Twin -- https://github.com/cosmos72/twin (storic)
• VWM -- https://vwm.sourceforge.net/index.html
• Zellij -- https://github.com/zellij-org/zellij (recent)
• Jexer -- https://jexer.sourceforge.io/
• Desktop-TUI -- https://github.com/Julien-cpsn/desktop-tui (rust)
• Monotty Desktop
• VTM

Other mentions

• https://en.wikipedia.org/wiki/Sixel -- terminal graphics
• https://chawan.net -- text mode browser with css, js, image support
• https://github.com/saitoha/xserver-sixel
• TurboVision port -- https://github.com/magiblot/tvision

Source: r/linux

Resources

• HP, Tutorial, FAQ, Docs
• awesome fish
• fish-shell cookbook
• Wikipedia

Extensions

• fisher plugin manager (list)

  • anicode find arbitrary unicode characters matching a search pattern
  • autoenvstack folder custom env set/restore
  • cprintf printf with colors
  • g2 friendly git command line client
  • getopts command line options parser
  • gitignore create .gitignore files from https://www.gitignore.io templates
  • paths create or append to environment variables
  • rvm rvm support
  • spark sparkline generator (cli histograms)
  • spin background job spinner
  • termcolours list available terminal colour names
  • upto change to the closest parent folder by name

• oh-my-fish plugin manager (list)

  • peco interactive history search
  • dpaste quickly share text on pastebin sites
  • git-flow completion support for git-flow
  • weather
  • bundler use Ruby's Bundler automatically for some commands
  • battery battery status utility
  • plugin-docker-machine easy machine set env

• prompt themes (see powerline and nerd fonts):

  • oh-my-fish bobthefish: powerline-style, git-aware theme
  • fisher metro powerline prompt optimized for speed and space
  • fisher nitro color-smart powerline prompt based in Metro
  • fisher segment powerline prompt builder

• midnight commander wrapper

• RVM integration via lunks/fish-nuggets

Prompt power-up

• decompress fish_config.7z attachment in ~/.config/fish/
• curl -L https://get.oh-my.fish | fish
• omf install bobthefish
• download and install Meslo font from nerd-fonts
• set MesloLGMDZ Nerd Font Mono font for your terminal
• put set -g theme_nerd_fonts yes in your ~/.config/fish/config.fish
• customize fish_greeting.fish and fish_right_prompt.fish in ~/.config/fish/functions/

On cygwin under windows you can install DejaVu Sans Mono ttf powerline font, and set fish as the default shell.

In the attached file there is a simple prompt with git support.

Commands

• fish_update_completions -- scan man pages for completion tips
• env VAR1=xxx VAR2=yyy command arg1 arg2 ... -- run command with env vars

A general tunnel command:

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ssh myuser@mysrv
  -L   8080:localhost:80  # tunnel local_port:target:target_port
  -L *:8080:localhost:80  # tunnel open to everyone who can connect to this machine
  -R   3380:localhost:80  # reverse tunnel port_on_mysrv:target:target_port
  -R *:3322:localhost:22  # reverse tunnel open to everyone who can connect to mysrv
  -q # quiet mode
  -f # go to background
  -n # redirects stdin from /dev/null
  -N # do not execute a remote command
  -T # disable pseudo-terminal allocation
  -M -S /path/to/socket # enable master mode via a shared socket
  -o UserKnownHostsFile=/dev/null # do not update known_hosts file
  -o StrictHostKeyChecking=no     # do no check the empty known_hosts file

Note: to allow the creation of reverse tunnels opened to everyone (0.0.0.0) you have to set this option:

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# server configuration: /etc/ssh/sshd_config
GatewayPorts clientspecified

Scriptable tunnels

You can look for process IDs via pgrep/pkill:

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ssh -fnNT ... mysrv          # start
pkill -f -QUIT 'ssh.*mysrv'  # stop

or better use master mode to avoid both grepping and any timing issues:

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ssh -fNM -S /path/to/socket ... mysrv  # start
ssh -S /path/to/socket -O check        # check
ssh -S /path/to/socket -O exit mysrv   # stop

Auto-closing tunnels

SSH runs the specified command and then exits only if no one is using the tunnel:

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ssh -f myusr@mysrv sleep 10  # start auto-closing tunnel
vncviewer 127.0.0.1::25901   # use the tunnel

Keep alive your connection

Keep alive the connection for 60 seconds, 1440 times (= 24 hours):

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# client configuration: /etc/ssh/ssh_config | ~/.ssh/config
Host *
  ServerAliveInterval 60
  ServerAliveCountMax 1440

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# server configuration: /etc/ssh/sshd_config
ClientAliveInterval 60
ClientAliveCountMax 1440

Test connectivity

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ssh -o BatchMode=yes -o ConnectTimeout=3 myusr@mysrv exit && echo ok || echo ko

List active tunnels and ports

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sudo lsof -i -n | egrep sshd

Port knocking

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# -4=ip4, -z=scan, -n=no_dns_lookup, -u=UDP, -v=verbose, -w=timeout_seconds
nc -4znuv hostname_or_ip port1 port2 ...

# example using TCP and wait interval 
nc -4zw myhost port1; sleep 1
nc -4zw myhost port2; sleep 1
...

Source: Stackexchange - master mode, Patrickmn - keep alive, Stackoverflow - test, Superuser - list active tunnels

runuser

Only root can use it, no password asked, less overhead than others.

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runuser -u username -- command args

# -l = login shell, -P = allocate a pty
runuser -l  userNameHere -c 'command args'
runuser -P -l  userNameHere -c '/user/bin/bash -ilc "command args"'

Note: You can also use #!/usr/bin/env -S bash -il shebang in a command script to get the real final user environment.

sudo

Asking user password

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# -i = login shell, -u = username
sudo -iu username # open default shell for `username`
sudo -iu username command args

Without asking user password

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echo "username ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/local

su

Asks target password.

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# - or --login = login shell
su - # open root shell
su - username -c "command args"

Source: nixCraft