prompt.sh

#!/bin/bash

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="\[\e[0m\]"

GIT_BRANCH_RE="^# On branch ([^${IFS}]*)"
GIT_REMOTE_RE="# Your branch is (.*) '"
GIT_GAP_RE="# Your branch is .* ([0-9]+) commits?\."
GIT_DIVERGE_RE="# Your branch and (.*) have diverged"


function gen_prompt {
    if [ ! -d "$(pwd)/.git" ]; then
        git_infos=""
    else
        git_status="$(git status 2> /dev/null)"
        
        # Handle uncommited changes
        if [[ ! ${git_status} =~ "working directory clean" ]]; then
            state="${RED}⚡"
        else
            state=""
        fi

        # Handle commits gap with remote
        if [[ ${git_status} =~ ${GIT_REMOTE_RE} ]]; then
            if [[ ${BASH_REMATCH[1]} == "ahead of" ]]; then
                remote="${YELLOW}↑"
                remote_sign="+"
            else
                remote="${YELLOW}↓"
                remote_sign="-"
            fi
            if [[ ${git_status} =~ ${GIT_GAP_RE} ]]; then
                remote="${remote}${remote_sign}${BASH_REMATCH[1]}"
            fi
        else
            remote=""
        fi

        # Handle diverged branches
        if [[ ${git_status} =~ ${GIT_DIVERGE_RE} ]]; then
            remote="${YELLOW}↕"
        fi

        # Generate git informations summary
        if [[ ${git_status} =~ ${GIT_BRANCH_RE} ]]; then
            branch=${BASH_REMATCH[1]}
            git_infos="(${branch})${remote}${state}"
        else
            git_infos=""
        fi
    fi

    # Last command's return value
    if [ $? -eq 0 ]; then
        last_ret="${GREEN}$?↩${COLOR_NONE}"
    else
        last_ret="${RED}$?↩${COLOR_NONE}"
    fi

    date_prefix="(${YELLOW}$(date +'%H:%M:%S')${COLOR_NONE})"
    main_part="${YELLOW}\u@\h${LIGHT_GRAY}:${BLUE}\w"
    PS1="${date_prefix}${LIGHT_GRAY}[${main_part}${GREEN}${git_infos}${LIGHT_GRAY}]${COLOR_NONE}${last_ret} \n\$ "
}

PROMPT_COMMAND="gen_prompt"