Powerline style prompt for Bash (and now, ZSH)

A Powerline like prompt for Bash/ZSH:

• Shows some important details about the git branch:
  • Displays the current git branch which changes background color when the branch is dirty
  • A '+' appears when untracked files are present
  • When the local branch differs from the remote, the difference in number of commits is shown along with '⇡' or '⇣' indicating whether a git push or pull is pending
• Changes color if the last command exited with a failure code
• If you're too deep into a directory tree, shortens the displayed path with an ellipsis
• Shows the current Python virtualenv environment
• It's all done in a Python script, so you could go nuts with it

Setup

• This script uses ANSI color codes to display colors in a terminal. These are notoriously non-portable, so may not work for you out of the box, but try setting your $TERM to xterm-256color, because that works for me.

• Patch the font you use for your terminal: see https://github.com/Lokaltog/vim-powerline/wiki/Patched-fonts

• Clone this repository somewhere:

    git clone https://github.com/milkbikis/powerline-shell
  

• Create a symlink to the python script in your home:

    ln -s <path/to/powerline-shell.py> ~/powerline-shell.py
  

  If you don't want the symlink, just modify the path in the commands below

• Now add the following to your .bashrc:

    function _update_ps1() {
       export PS1="$(~/powerline-shell.py $?)"
    }
  
    export PROMPT_COMMAND="_update_ps1"
  

• ZSH fans, add the following to your .zshrc:

    function powerline_precmd() {
      export PS1="$(~/powerline-shell.py $? --shell zsh)"
    }
  
    function install_powerline_precmd() {
      for s in "${precmd_functions[@]}"; do
        if [ "$s" = "powerline_precmd" ]; then
          return
        fi
      done
      precmd_functions+=(powerline_precmd)
    }
  
    install_powerline_precmd
  

• Fish users, redefine fish_prompt in ~/.config/fish/config.fish:

    function fish_prompt
        ~/powerline-shell.py $status --shell bare
    end