Linux Bash Aliases

Bash aliases are essentially keyboard shortcuts or abbreviations for longer command sequences. If, for example, we include alias lm="ls -l | more" in ~/.bashrc, typing lm gets automatically replaced with ls -l | more. Here are some of my aliases and helper functions,

alias ..='cd ..'
alias ...='cd ../..'
alias install='sudo apt-get install'
# Open aliases for editing and source afterward
alias aliases='sudo gedit $HOME/.bash_aliases && source $HOME/.bash_aliases'

google() {
  search=""
  echo "$1"
  for term in $*; do
    search="$search%20$term"
  done
  xdg-open "http://www.google.com/search?q=$search"
}

extract() {
  if [-f $1] ; then
    case $1 in
      *.tar.bz2) tar xvjf $1;;
      *.tar.gz) tar xvzf $1;;
      *.bz2) bunzip2 $1;;
      *.rar) rar x $1;;
      *.gz) gunzip $1;;
      *.tar) tar xvf $1;;
      *.tbz2) tar xvjf $1;;
      *.tgz) tar xvzf $1;;
      *.zip) unzip $1;;
      *.Z) uncompress $1;;
      *.7z) 7z x $1;;
      *) echo "Don't know how to extract '$1'..." ;;
    esac
  else
    echo "'$1' is not a valid file!"
  fi
}