bash prompt

# ANSI CODES - SEPARATE MULTIPLE VALUES WITH ;
#
#  0  reset          4  underline
#  1  bold           7  inverse
#
# FG  BG  COLOR     FG  BG  COLOR
# 30  40  black     34  44  blue
# 31  41  red       35  45  magenta
# 32  42  green     36  46  cyan
# 33  43  yellow    37  47  white

if [[ ! "${prompt_colors[@]}" ]]; then
  prompt_colors=(
    "1;31" # information color
    "1;30" # bracket color
    "31" # error color
  )

  if [[ "$SSH_TTY" ]]; then
    # connected via ssh
    prompt_colors[1]="1;33"
  elif [[ "$USER" == "root" ]]; then
    # logged in as root
    prompt_colors[1]="1;44"
  fi
fi

# Inside a prompt function, run this alias to setup local $c0-$c9 color vars.
alias prompt_getcolors='prompt_colors[9]=; local i; for i in ${!prompt_colors[@]}; do local c$i="\[\e[0;${prompt_colors[$i]}m\]"; done'

# Git status.
function prompt_git() {
  prompt_getcolors
  local status output flags
  status="$(git status 2>/dev/null)"
  [[ $? != 0 ]] && return;
  output="$(echo "$status" | awk '/# Initial commit/ {print "(init)"}')"
  [[ "$output" ]] || output="$(echo "$status" | awk '/# On branch/ {print $4}')"
  [[ "$output" ]] || output="$(git branch | perl -ne '/^\* (.*)/ && print $1')"
  flags="$(
    echo "$status" | awk 'BEGIN {r=""} \
      /^# Changes to be committed:$/        {r=r "+"}\
      /^# Changes not staged for commit:$/  {r=r "!"}\
      /^# Untracked files:$/                {r=r "?"}\
      END {print r}'
  )"
  if [[ "$flags" ]]; then
    output="$output$c1:$c0$flags"
  fi
  echo "$c1-$c0$output$c1$c9"
}
# Maintain a per-execution call stack.
prompt_stack=()
trap 'prompt_stack=("${prompt_stack[@]}" "$BASH_COMMAND")' DEBUG

function prompt_command() {
  local exit_code=$?
  # If the first command in the stack is prompt_command, no command was run.
  # Set exit_code to 0 and reset the stack.
  [[ "${prompt_stack[0]}" == "prompt_command" ]] && exit_code=0
  prompt_stack=()

  # Manually load z here, after $? is checked, to keep $? from being clobbered.
  [[ "$(type -t _z)" ]] && _z --add "$(pwd -P 2>/dev/null)" 2>/dev/null

  # While the simple_prompt environment var is set, disable the awesome prompt.
  [[ "$simple_prompt" ]] && PS1='\n$ ' && return

  prompt_getcolors
  PS1="\n"
  # misc: [cmd#]
  #PS1="$PS1$c1[$c0#\#$c1]$c9"
  # name: user@host:path
  PS1="$PS1\[\033[0;36m\]\u$c1@\[\033[0;36m\]\h$c1:\[\033[0;37m\]\w$c9"
  # git: [branch:flags]
  PS1="$PS1$(prompt_git)"
  PS1="$PS1 $c0\$\[\033[0;37m\] "
}

PROMPT_COMMAND="prompt_command"