my_ps1.sh

function parse_git_branch {
    git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1) /'
}

function git_unadded_new {
    if git rev-parse --is-inside-work-tree &> /dev/null
    then
        if [[ -z $(git ls-files --other --exclude-standard 2> /dev/null) ]]
        then
            echo ""
        else
            echo "@ "
        fi
    fi
}

function git_needs_commit {
    if [[ "git rev-parse --is-inside-work-tree &> /dev/null)" != 'true' ]] && git rev-parse --quiet --verify HEAD &> /dev/null
    then
        git diff-index --cached --quiet --ignore-submodules HEAD 2> /dev/null
        (( $? && $? != 128 )) && echo "@ "
    fi
}

function git_modified_files {
    if [[ "git rev-parse --is-inside-work-tree &> /dev/null)" != 'true' ]] && git rev-parse --quiet --verify HEAD &> /dev/null
    then
        git diff --no-ext-diff --ignore-submodules --quiet --exit-code || echo "@ "
    fi
}

function short_pwd {
    echo $PWD | sed "s:${HOME}:~:" | sed "s:/\(.\)[^/]*:/\1:g" | sed "s:/[^/]*$:/$(basename $PWD):"
}

if [ `id -u` = 0 ]; then
    COLOUR="04;01;31m"
    PATH_COLOUR="01;31m"
else
    COLOUR="01;32m"
    PATH_COLOUR="01;34m"
fi

BOLD_RED="01;31m"
BOLD_GREEN="01;32m"
BOLD_BLUE="01;34m"

PS1='${debian_chroot:+($debian_chroot)}\[\033[$COLOUR\]\u@\h\[\033[00m\]:\[\033[01;$PATH_COLOUR\]$(short_pwd)\[\033[00m\]\[\033[01;35m\]$(parse_git_branch)\[\033[00m\]\[\033[$BOLD_RED\]$(git_unadded_new)\[\033[00m\]\[\033[$BOLD_GREEN\]$(git_needs_commit)\[\033[00m\]\[\033[$BOLD_BLUE\]$(git_modified_files)\[\033[00m\]> '