.bash_prompt

prompt_git() {
    local status='';
    local branch_name='';

    # Check if the current directory is in a Git repository.
    git rev-parse --is-inside-work-tree &> /dev/null || return;

    # Check for what branch we’re on. Get the short symbolic ref. If HEAD
    # isn’t a symbolic ref, get a tracking remote branch or tag. Otherwise,
    # get the short SHA for the latest commit, or give up.
    branch_name="$(git symbolic-ref --quiet --short HEAD 2> /dev/null || \
                   git describe --all --exact-match HEAD 2> /dev/null || \
                   git rev-parse --short HEAD 2> /dev/null || \
                   echo '(unknown)')";

    # Early exit for Chromium & Blink repo, as the dirty check takes too long.
    # github.com/paulirish/dotfiles/blob/dd33151f/.bash_prompt#L110-L123
    repoUrl="$(git config --get remote.origin.url)";
    if grep -q 'chromium/src.git' <<< "${repoUrl}"; then
        status+='*';
    else
        # Check for uncommitted changes in the index.
        if ! $(git diff --quiet --ignore-submodules --cached); then
            status+='C'; # '+'
        fi;

        # Check for unstaged changes.
        if ! $(git diff-files --quiet --ignore-submodules --); then
            status+='S'; # '!'
        fi;

        # Check for untracked files.
        if [ -n "$(git ls-files --others --exclude-standard)" ]; then
            status+='T'; # '?'
        fi;

        # Check for stashed files.
        if $(git rev-parse --verify refs/stash &> /dev/null); then
            status+='U'; # '$'
        fi;
    fi;

    [ -n "${status}" ] && status=" [${status}]";

    echo -e "${1}${branch_name}${2}${status}";
}

# Search for '256 colors chart' to learn more.
red=$(tput setaf 203);
orange=$(tput setaf 208);
yellow=$(tput setaf 228);
green=$(tput setaf 2);
white=$(tput setaf 15);
blue=$(tput setaf 6);
reset=$(tput sgr0);

# Highlight the user name when logged in as root.
if [[ "${USER}" == "root" ]]; then
    user_style="${red}";
else
    user_style="${orange}";
fi;

# Highlight the hostname when connected via SSH.
if [[ "${SSH_TTY}" ]]; then
    host_style="${red}";
else
    host_style="${yellow}";
fi;

# {username}
PS1="\[${user_style}\]\u";
# at
PS1+="\[${white}\] at ";
# {host}
PS1+="\[${host_style}\]\h";
# in
PS1+="\[${white}\] in ";
# {working directory}
PS1+="\[${green}\]\W";
# {git details}
PS1+="\$(prompt_git \"\[${white}\] on \[${blue}\]\" \"\[${blue}\]\")";
# new line
PS1+="\n";
# '$' and reset color
PS1+="\[${white}\]\$ \[${reset}\]";