bash script to include Git and Mercurial branch and status in command prompt

git_hg_bash_prompt.sh

#!/bin/bash
#
# DESCRIPTION:
#
#   Set the bash prompt according to:
#    * the branch/status of the current git repository
#    * the branch of the current subversion repository
#    * the return value of the previous command
#
# USAGE:
#
#   1. Save this file as ~/.git_svn_bash_prompt
#   2. Add the following line to the end of your ~/.profile or ~/.bash_profile:
#        . ~/.git_svn_bash_prompt
#
# AUTHOR:
#
#   Scott Woods <scott@westarete.com>
#   West Arete Computing
#
#   Based on work by halbtuerke and lakiolen.
#
#   http://gist.github.com/31967


# The various escape codes that we can use to color our prompt.
        RED="\[\033[0;31m\]"
     YELLOW="\[\033[0;33m\]"
       CYAN="\[\033[0;36m\]"
       BLUE="\[\033[0;34m\]"
      GREEN="\[\033[0;32m\]"
  LIGHT_RED="\[\033[1;31m\]"
LIGHT_GREEN="\[\033[1;32m\]"
LIGHT_YELLOW="\[\033[1;33m\]"
 LIGHT_BLUE="\[\033[1;34m\]"
      WHITE="\[\033[1;37m\]"
 LIGHT_GRAY="\[\033[0;37m\]"
 COLOR_NONE="\[\e[0m\]"
     NORMAL="\[\033[0m\]"

# Detect whether the current directory is a git repository.
function is_git_repository {
  # this only checks if the current directory is a git repo
  #test -d .git
  # this checks if the current or parent dir is a git repo
  git status > /dev/null 2>&1
}

# Detect whether the current directory is a hg repository.
function is_hg_repository {
  test -d .hg
}

# Determine the branch/state information for this git repository.
function set_git_branch {
  # Capture the output of the "git status" command.
  git_status="$(git status 2> /dev/null)"

  # Set color based on clean/staged/dirty.
  if [[ ${git_status} =~ "Untracked files" ]]; then
    remote=""
    state="${RED}"
  elif [[ ${git_status} =~ "not staged" ]]; then
    remote=""
    state="${RED}"
  elif [[ ${git_status} =~ "Changes to be committed" ]]; then
    remote=""
    state="${YELLOW}"
  # Set arrow icon based on status against remote.
  elif [[ ${git_status} =~ "Your branch is ahead" ]]; then
    remote="↑"
    state="${GREEN}"
  elif [[ ${git_status} =~ "Your branch is behind" ]]; then
    remote="↓"
    state="${RED}"
  elif [[ ${git_status} =~ "Your branch and (.*) have diverged" ]]; then
    remote="↕"
    state="${YELLOW}"
  else
    remote=""
    state="${CYAN}"
  fi

  # Get the name of the branch.
  branch_pattern="On branch ([^${IFS}]*)"
  if [[ ${git_status} =~ ${branch_pattern} ]]; then
    branch=${BASH_REMATCH[1]}
  fi

  # Set the final branch string.
  BRANCH="${state}(${branch})${remote}${COLOR_NONE} "
}

# Determine the branch information for this hg repository.
function set_hg_branch {
 # Capture the output of the "hg summary" command.
   hg_status="$(hg summary 2> /dev/null)"

   localstate="${GREEN}"

   #remote=""
   #remotestate=""
   remote_out="↑"
   remote_in="↓"
   remotestate_out=""
   remotestate_in=""

   # Set color based on clean/staged/dirty.
   if [[ ${hg_status} =~ "added" ]]; then
     localstate="${YELLOW}"
   elif [[ ${hg_status} =~ "modified" ]]; then
     localstate="${LIGHT_YELLOW}"
   elif [[ ${hg_status} =~ "unknown" ]]; then
     localstate="${LIGHT_BLUE}"
   fi

   if [[ ${check_threshold} -lt 1 ]] || [[ ${check_threshold} -gt 10 ]]; then
      hg_status_remote="$(hg summary --remote 2> /dev/null)"
      check_threshold=1
   else
      check_threshold=$((check_threshold+1))
   fi

   #if [[ ${hg_status_remote} =~ "outgoing" ]] && [[ ${hg_status_remote} =~ "incoming" ]]; then
   #  remote="↕"
   #  remotestate="${YELLOW}"
   #elif [[ ${hg_status_remote} =~ "incoming" ]]; then
   #  remote="↓"
   #  remotestate="${RED}"
   #elif [[ ${hg_status_remote} =~ "outgoing" ]]; then
   #  remote="↑"
   #  remotestate="${GREEN}"
   #else
   #  remotestate="${CYAN}"
   #fi

   # Set arrow icon based on status against remote.
   if [[ ${hg_status_remote} =~ "incoming" ]]; then
     remotestate_in="${RED}"
   else
     remotestate_in="${GREEN}"
   fi
   if [[ ${hg_status_remote} =~ "outgoing" ]]; then
     remotestate_out="${RED}"
   else
     remotestate_out="${GREEN}"
   fi

   # Get the name of the branch.
   branch=$(hg branch 2> /dev/null)

   # Set the final branch string.
   #BRANCH="${localstate}(${branch})${remotestate} ${remote}${COLOR_NONE} "
   BRANCH="${localstate}(${branch}) ${remotestate_out}${remote_out}${remotestate_in}${remote_in}${COLOR_NONE} "
}

# Return the prompt symbol to use, colorized based on the return value of the
# previous command.
function set_prompt_symbol () {
  if test $1 -eq 0 ; then
      PROMPT_SYMBOL="\$"
  else
      PROMPT_SYMBOL="${RED}\$${COLOR_NONE}"
  fi
}

# Set the full bash prompt.
function set_bash_prompt () {
  # Set the PROMPT_SYMBOL variable. We do this first so we don't lose the
  # return value of the last command.
  set_prompt_symbol $?

  # Set the BRANCH variable.
  if is_git_repository ; then
    set_git_branch
  elif is_hg_repository ; then
    set_hg_branch
  else
    BRANCH=''
  fi

  # Set the bash prompt variable.
  #PS1="[ ${MAGENTA}\u@\h ${LIGHT_GREEN}\w ${BRANCH}${NORMAL}]\n${BLUE}\$${NORMAL} "
  PS1="\w ${BRANCH}${NORMAL}\n\u@\h \$ "

  # in iTerm2 windows, set tab title to the current directory
  if [ $ITERM_SESSION_ID ]; then
    echo -ne "\033];${PWD##*/}\007";
  fi
}

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