bash_prompt

#!/bin/bash
# Filename:      bash_prompt
# Maintainer:    Felipe Fink Grael
#
# Based on Dave Vehr's work, found at
# http://www.debian-administration.org/articles/205

# Current Format: [dynamic section] USER@HOST:PWD$
# USER:      (also sets the base color for the prompt)
#   Red       == Root(UID 0) Login shell (i.e. sudo bash)
#   Light Red == Root(UID 0) Login shell (i.e. su -l or direct login)
#   Yellow    == Root(UID 0) priviledges in non-login shell (i.e. su)
#   Brown     == SU to user other than root(UID 0)
#   Green     == Normal user
# @:
#   Light Red == http_proxy environmental variable undefined.
#   Green     == http_proxy environmental variable configured.
# HOST:
#   Red       == Insecure remote connection (unknown type)
#   Yellow    == Insecure remote connection (Telnet)
#   Brown     == Insecure remote connection (RSH)
#   Cyan      == Secure remote connection (i.e. SSH)
#   Green     == Local session
# DYNAMIC SECTION:
#     (If count is zero for any of the following, it will not appear)
#   [scr:#] ==== Number of detached screen sessions
#     Yellow    == 1-2
#     Red       == 3+
#   [bg:#]  ==== Number of backgrounded but still running jobs
#     Yellow    == 1-10
#     Red       == 11+
#   [stp:#] ==== Number of stopped (backgrounded) jobs
#     Yellow    == 1-2
#     Red       == 3+
# CURRENT DIRECTORY:     (truncated to 1/4 screen width)
#   Red       == Current user does not have write priviledges
#   Green     == Current user does have write priviledges
# NOTE:
#   1.  Displays message on day change at midnight on the line above the
#       prompt (Day changed to...).
#   2.  Command is added to the history file each time you hit enter so its
#       available to all shells.

# Configure Colors:
COLOR_WHITE='\033[1;37m'
COLOR_LIGHTGRAY='\033[0;37m'
COLOR_GRAY='\033[1;30m'
COLOR_BLACK='\033[0;30m'
COLOR_RED='\033[0;31m'
COLOR_LIGHTRED='\033[1;31m'
COLOR_GREEN='\033[0;32m'
COLOR_LIGHTGREEN='\033[1;32m'
COLOR_BROWN='\033[0;33m'
COLOR_YELLOW='\033[1;33m'
COLOR_BLUE='\033[0;34m'
COLOR_LIGHTBLUE='\033[1;34m'
COLOR_PURPLE='\033[0;35m'
COLOR_PINK='\033[1;35m'
COLOR_CYAN='\033[0;36m'
COLOR_LIGHTCYAN='\033[1;36m'
COLOR_DEFAULT='\033[0m'

# Color scheme
COLOR_RETVAL="\[${COLOR_RED}\]"

COLOR_GIT="\[${COLOR_BLUE}\]"

COLOR_SCREEN_LOTS="\[${COLOR_YELLOW}\]"
COLOR_SCREEN_FEW="\[${COLOR_CYAN}\]"

COLOR_BGJOBS_LOTS="\[${COLOR_YELLOW}\]"
COLOR_BGJOBS_FEW="\[${COLOR_CYAN}\]"

COLOR_STPJOBS_LOTS="\[${COLOR_YELLOW}\]"
COLOR_STPJOBS_FEW="\[${COLOR_CYAN}\]"

COLOR_USER_ROOT="\[${COLOR_LIGHTRED}\]"
COLOR_USER_NORMAL="\[${COLOR_CYAN}\]"

COLOR_DISPLAY_OK="\[${COLOR_LIGHTCYAN}\]"
COLOR_DISPLAY_NOXAUTH="\[${COLOR_LIGHTGRAY}\]"
COLOR_DISPLAY_NODISPLAY="\[${COLOR_LIGHGRAY}\]"

COLOR_HOST_SSH="\[${COLOR_LIGHTCYAN}\]"
COLOR_HOST_LOCAL="\[${COLOR_CYAN}\]"

COLOR_USER_ROOT="\[${COLOR_LIGHTRED}\]"
COLOR_USER_NORMAL="\[${COLOR_CYAN}\]"

COLOR_COLON_ROOT="\[${COLOR_LIGHTRED}\]"
COLOR_COLON_NORMAL="\[${COLOR_CYAN}\]"

COLOR_DOLLAR_ROOT="\[${COLOR_LIGHTRED}\]"
COLOR_DOLLAR_NORMAL="\[${COLOR_CYAN}\]"

COLOR_PWD_WRITABLE="\[${COLOR_WHITE}\]"
COLOR_PWD_NONWRITABLE="\[${COLOR_LIGHTGRAY}\]"

COLOR_HISTORY="\[${COLOR_LIGHTGRAY}\]"

COLOR_VIRTUALENV="\[${COLOR_GREEN}\]"

# Function to set prompt_command to.
function promptcmd () {
    local RET_VAL=$?
    history -a
    local SSH_FLAG=0
#    local TTY=$(tty | awk -F/dev/ '{print $2}')
#    if [[ ${TTY} ]]; then
#        local SESS_SRC=$(who | grep "$TTY "  | awk '{print $6 }')
#    fi

    # Titlebar - commented out as Terminal.app seems to have its own way
    case ${TERM} in
        xterm* )
            local TITLEBAR='\[\033]0;\u@\h:\w\007\]'
            ;;
        screen* )
            local TITLEBAR='\[\033k\u@\h:\w\033\134\]'
            ;;
        *       )
            local TITLEBAR=''
            ;;
    esac

    # Bash history number
    local PHIST="${COLOR_HISTORY}\\!:"

    # Virtualenv
    local PVENV=""
    if [ "x$VIRTUAL_ENV" != x ] ; then
        PVENV="${COLOR_VIRTUALENV}$(basename ${VIRTUAL_ENV}): "
    fi

    # Last Command's Return Value
    local PRETVAL=''
    if [ $RET_VAL -ne 0 ] ; then
        PRETVAL="${COLOR_RETVAL}[${RET_VAL}] "
    fi

    # Git branch
    local PGIT=''
    if `which git >/dev/null 2>&1`; then
        local GIT_BRANCH="$(git branch 2>&1 | grep '*' | cut -f 2 -d ' ')"
        if [ -n "$GIT_BRANCH" ]; then
            PGIT="${COLOR_GIT}($GIT_BRANCH) "
        fi
    fi

    # Detached Screen Sessions
    if `wich screen >/dev/null 2>&1`; then
        local DTCHSCRN=$(screen -ls | grep -c Detach )
        local PSCREEN=''
        if [ ${DTCHSCRN} -gt 2 ]; then
            PSCREEN="${COLOR_SCREEN_LOTS}[scr:${DTCHSCRN}] "
        elif [ ${DTCHSCRN} -gt 0 ]; then
            PSCREEN="${COLOR_SCREEN_FEW}[scr:${DTCHSCRN}] "
        fi
    fi

    # Backgrounded running jobs
    local BKGJBS=$(jobs -r | wc -l | sed -e 's/ *//g' )
    local PBGJOBS=''
    if [ ${BKGJBS} -gt 2 ]; then
        PBGJOBS="${COLOR_BGJOBS_LOTS}[bg:${BKGJBS}] "
    elif [ ${BKGJBS} -gt 0 ]; then
        PBGJOBS="${COLOR_BGJOBS_FEW}[bg:${BKGJBS}] "
    fi

    # Stopped Jobs
    local STPJBS=$(jobs -s | wc -l | sed -e 's/ *//g' )
    local PSTPJOBS=''
    if [ ${STPJBS} -gt 2 ]; then
        PSTPJOBS="${COLOR_BGJOBS_LOTS}[stp:${STPJBS}] "
    elif [ ${STPJBS} -gt 0 ]; then
        PSTPJOBS="${COLOR_BGJOBS_FEW}[stp:${STPJBS}] "
    fi

    # User dependant features (username, colon and dollar sign)
    local PUSER=''
    local PCOLON=''
    local PDOLLAR=''
    if [ ${UID} -eq 0 ] ; then
        PUSER="${COLOR_USER_ROOT}\u"
        PCOLON="${COLOR_COLON_ROOT}:"
        PDOLLAR="${COLOR_DOLLAR_ROOT}#"
    else
        PUSER="${COLOR_USER_NORMAL}\u"
        PCOLON="${COLOR_COLON_NORMAL}:"
        PDOLLAR="${COLOR_DOLLAR_NORMAL}$"
    fi

    # DISPLAY situation
    local PAT=''
    if [ -n "$DISPLAY" ] ; then
        if [ -n "$XAUTHORITY" ] ; then
            if [ -f $XAUTHORITY ] ; then
                PAT="${COLOR_DISPLAY_OK}@"
            else
                PAT="${COLOR_DISPLAY_NOXAUTH}@"
            fi
        else
            PAT="${COLOR_DISPLAY_NOXAUTH}@"
        fi
    else
        PAT="${COLOR_DISPLAY_NODISPLAY}@"
    fi

    # Host
    local PHOST=''
    if [[ ${SSH_CLIENT} ]] || [[ ${SSH2_CLIENT} ]]; then
        SSH_FLAG=1
    fi
    if [ ${SSH_FLAG} -eq 1 ]; then
        PHOST="${COLOR_HOST_SSH}\h"
    else
        PHOST="${COLOR_HOST_LOCAL}\h"
    fi

    # Working directory
    local PPWD=''
    if [ -w "${PWD}" ]; then
        PPWD="${COLOR_PWD_WRITABLE}$(prompt_workingdir)"
    else
        PPWD="${COLOR_PWD_NONWRITABLE}$(prompt_workingdir)"
    fi

    PS1="${TITLEBAR}${PHIST}${PVENV}${PRETVAL}${PGIT}${PSCREEN}${PBGJOBS}${PSTPJOBS}${PUSER}${PAT}${PHOST}${PCOLON}${PPWD}${PDOLLAR}\[${COLOR_DEFAULT}\] "
}

# Trim working dir to 1/4 the screen width
function prompt_workingdir () {

  # Workaround for the case where the COLUMN variable isnt set yet.
  if [ -z "$COLUMNS" ]; then
          local COLUMNS=80
  fi

  local pwdmaxlen=$(($COLUMNS/4))
  local trunc_symbol="..."
  if [[ $PWD == $HOME* ]]; then
    newPWD="~${PWD#$HOME}"
  else
    newPWD=${PWD}
  fi
  if [ ${#newPWD} -gt $pwdmaxlen ]; then
    local pwdoffset=$(( ${#newPWD} - $pwdmaxlen + 3 ))
    newPWD="${trunc_symbol}${newPWD:$pwdoffset:$pwdmaxlen}"
  fi
  echo $newPWD
}

# Determine what prompt to display:
# 1.  Display simple custom prompt for shell sessions started
#     by script.
# 2.  Display "bland" prompt for shell sessions within vim
# 3   Display promptcmd for all other cases.

function load_prompt () {
    # Get PIDs
    #local my_process=$(cat /proc/$$/cmdline | cut -d \. -f 1)

    if [ `uname -s` != "Linux" ]; then
            local parent_process=unknown
    else
            local parent_process=$(cat /proc/$PPID/cmdline | cut -d \. -f 1)
    fi

    if  [[ $parent_process == script* ]]; then
        PROMPT_COMMAND=""
        PS1="\u@\H:\w\$ "
    elif [[ $parent_process == vim* || $parent_process == gvim* ]]; then
        PROMPT_COMMAND=""
        PS1="\u@\H:\w\$ "
    else
        PROMPT_COMMAND=promptcmd
     fi
    export PS1 PROMPT_COMMAND
}

load_prompt