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Shell

cheatsheets:

bash basics

conditions

  • check if file exists: 
    [ -f /path/to/file ] && do something
if [ -f /path/to/file ]; then do something; fi

find biggest folders of current directory

du -hs * | sort -rh | head -5

default text editor

  • for inline shell call: sudo EDITOR=nano crontab -e

  • add to ~/.bashrc or ~/.zshrc:

    • export EDITOR=nano

  • for default root editor, edit also /root/.bashrc or /root/.zshrc

echo "export VISUAL=nano\nexport EDITOR=nano" >> ~/.bashrc
echo "export VISUAL=nano\nexport EDITOR=nano" >> ~/.zshrc

sudo sh -c "echo -e \"export VISUAL=nano\nexport EDITOR=nano\" >> ~/.bashrc"
sudo sh -c "echo -e \"export VISUAL=nano\nexport EDITOR=nano\" >> ~/.zshrc"

login message:

  • for local user edit: nano ~/.profile
  • for global: /etc/profile or /etc/bashrc (only for bash shell)

add for example:

#shell login message
echo -e "\n\n You are working on: \t\e[41m>>> welding-shop.fronius.com <<<\e[49m\n\n"

custom shell prompt:

  • for local user edit: nano ~/.profile
  • for global: /etc/profile or /etc/bashrc (only for bash shell)

add for example:

#shell login message
alias PS1="\e[0;32m[\u@\h \w]\$ \e[0m"
  • \u - user
  • \h - host
  • \w - current path

[test@ubuntu1 ~]$ <- in green

PS3 for select prompt

https://www.thegeekstuff.com/2008/09/bash-shell-take-control-of-ps1-ps2-ps3-ps4-and-prompt_command/

Terminal colors

  • \e[0;32m

  • \e[ – Begin color changes

  • 0;32m – Specify the color code

  • [\u@\h \W]\$ – This is the code for your normal BASH prompt (username@hostname Workingdirectory $)

  • \e[0m – Exit color-change mode

The first number in the color code specifies the typeface:

  • 0 – Normal
  • 1 – Bold (bright)
  • 2 – Dim
  • 4 – Underlined

The second number indicates the color you want:

color background text
black \e[0;40m \e[0;30m
Red \e[0;41m \e[0;31m
Green \e[0;42m \e[0;32m
Brown \e[0;43m \e[0;33m
Blue \e[0;44m \e[0;34m
Purple \e[0;45m \e[0;35m
Cyan \e[0;46m \e[0;36m
Light gray \e[0;47m \e[0;37m

output redirection

  • 2>&1 redirect StdErr to StdOut
  • 2>&1 | redirect and Pipe, same as |& (not in sh)
          || visible in terminal ||   visible in file   || existing
  Syntax  ||  StdOut  |  StdErr  ||  StdOut  |  StdErr  ||   file   
==========++==========+==========++==========+==========++===========
    >     ||    no    |   yes    ||   yes    |    no    || overwrite
    >>    ||    no    |   yes    ||   yes    |    no    ||  append
          ||          |          ||          |          ||
   2>     ||   yes    |    no    ||    no    |   yes    || overwrite
   2>>    ||   yes    |    no    ||    no    |   yes    ||  append
          ||          |          ||          |          ||
   &>     ||    no    |    no    ||   yes    |   yes    || overwrite
   &>>    ||    no    |    no    ||   yes    |   yes    ||  append
          ||          |          ||          |          ||
 | tee    ||   yes    |   yes    ||   yes    |    no    || overwrite
 | tee -a ||   yes    |   yes    ||   yes    |    no    ||  append
          ||          |          ||          |          ||
|& tee    ||   yes    |   yes    ||   yes    |   yes    || overwrite
|& tee -a ||   yes    |   yes    ||   yes    |   yes    ||  append

zsh

install zsh

  • ZSH (shell with more features) sudo apt install zsh
  • Oh-My-ZSH sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"
  • install font for "powerlevel10k" https://github.com/romkatv/powerlevel10k#meslo-nerd-font-patched-for-powerlevel10k
  • choose font Meslo Nerd in preferences of the terminal or editor
  • install "powerlevel10k"-theme for ohmyzsh https://github.com/romkatv/powerlevel10k git clone --depth=1 https://github.com/romkatv/powerlevel10k.git ${ZSH_CUSTOM:-$HOME/.oh-my-zsh/custom}/themes/powerlevel10k
  • Set ZSH_THEME="powerlevel10k/powerlevel10k" in ~/.zshrc.
    • sed -i '/ZSH_THEME="/c\ZSH_THEME="powerlevel10k/powerlevel10k"' ~/.zshrc
  • Type p10k configure if the configuration wizard doesn't start automatically.

edit for visual studio code

  • Press command + shift + P in your VSCode window.
  • type settings.json and open it.
  • insert: 
    {
...
  "terminal.integrated.fontFamily": "MesloLGS NF",
  "terminal.integrated.defaultProfile.linux": "zsh"
...
}
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