Set color bash prompt according to git branch and virtualenv activation.

git_bash_prompt.sh

#!/bin/bash
#
# DESCRIPTION:
#
#   Set the bash prompt according to:
#    * the branch/status of the current git repository
#    * the name of the current virtualenv (if activated)
#
#   https://gist.github.com/hugorodgerbrown/4143150/
#
# USAGE:
#
#   1. Save this file as ~/.git_bash_prompt
#   2. Add the following line to the end of your ~/.profile or ~/.bash_profile:
#        . ~/.git_bash_prompt

# The various escape codes that we can use to color our prompt.
        RED="\[\033[0;31m\]"
     YELLOW="\[\033[0;33m\]"
      GREEN="\[\033[0;32m\]"
       BLUE="\[\033[0;34m\]"
  LIGHT_RED="\[\033[1;31m\]"
LIGHT_GREEN="\[\033[1;32m\]"
      WHITE="\[\033[1;37m\]"
 LIGHT_GRAY="\[\033[0;37m\]"
 COLOR_NONE="\[\e[0m\]"

PROMPT_SYMBOL="\$"

# Detect whether the current directory is a git repository.
function is_git_repository {
  git branch > /dev/null 2>&1
}

function set_git_state {
  # Set color based on clean/staged/dirty.
  if [[ ${git_status} =~ "working tree clean" ]]; then
    state="${GREEN}"
  elif [[ ${git_status} =~ "Changes to be committed" ]]; then
    state="${YELLOW}"
  else
    state="${RED}"
  fi
}

function set_git_remote {
  # Set arrow icon based on status against remote.
  if [[ ${git_status} =~ "Your branch is ahead of" ]]; then
    remote="+"
  elif [[ ${git_status} =~ "Your branch is behind" ]]; then
    remote="-"
  elif [[ ${git_status} =~ "Your branch is up-to-date" ]]; then
    remote=""
  elif [[ ${git_status} =~ "Your branch and (.*) have diverged" ]]; then
    remote="x"
  else
    remote="?"
  fi
}

# Determine the branch/state information for this git repository.
function set_git_status {
  # Capture the output of the "git status" command.
  if is_git_repository ; then
    git_status="$(git status 2> /dev/null)"
    set_git_state
    set_git_remote
    # Set the final branch string.
    BRANCH="${state}($(git rev-parse --abbrev-ref HEAD)${remote})${COLOR_NONE}"
  else
    BRANCH=""
  fi
}

# work out if there is a venv activated and set $VENV
function set_venv (){
  # Get Virtual Env
  if [[ $VIRTUAL_ENV != "" ]]
      then
        # Strip out the path and just leave the env name
        VENV="${YELLOW}[${VIRTUAL_ENV##*/}]${COLOR_NONE}"
  else
        # In case you don't have one activated
        VENV=''
  fi
}

function set_history_number () {
  HISTORY_NUMBER="${BLUE}\! ${COLOR_NONE}"
}

# Set the full bash prompt.
function set_bash_prompt () {

  set_venv
  set_git_status
  set_history_number

  PS1="${VENV} \w ${BRANCH} ${HISTORY_NUMBER}${PROMPT_SYMBOL} "

}

# Tell bash to execute this function just before displaying its prompt.
PROMPT_COMMAND=set_bash_prompt