Bash prompt for servers

.bashrc

#
# Clean and minimalistic Bash prompt
# Author: Artem Sapegin, sapegin.me
# 
# Inspired by: https://github.com/sindresorhus/pure & https://github.com/dreadatour/dotfiles/blob/master/.bash_profile
#
# Notes:
# - $local_username - username you don’t want to see in the prompt - can be defined in ~/.bashlocal : `local_username="admin"`
# - Colors ($RED, $GREEN) - defined in ../tilde/bash_profile.bash
#

# User color
case $(id -u) in
    0) user_color="${red}" ;;  # root
    *) user_color="${green}" ;;
esac

# Symbols
prompt_symbol="▲"
prompt_clean_symbol="☀ "
prompt_dirty_symbol="☂ "
prompt_venv_symbol="☁ "

function prompt_command() {
    # Local or SSH session?
    local remote=
    [ -n "$SSH_CLIENT" ] || [ -n "$SSH_TTY" ] && remote=1

    # Git branch name and work tree status (only when we are inside Git working tree)
    local git_prompt=
    if [[ "true" = "$(git rev-parse --is-inside-work-tree 2>/dev/null)" ]]; then
        # Branch name
        local branch="$(git symbolic-ref HEAD 2>/dev/null)"
        branch="${branch##refs/heads/}"

        # Working tree status (red when dirty)
        local dirty=
        # Modified files
        git diff --no-ext-diff --quiet --exit-code --ignore-submodules 2>/dev/null || dirty=1
        # Untracked files
        [ -z "$dirty" ] && test -n "$(git status --porcelain)" && dirty=1

        # Format Git info
        if [ -n "$dirty" ]; then
            git_prompt=" ${red}$prompt_dirty_symbol$branch${reset_color}"
        else
            git_prompt=" ${green}$prompt_clean_symbol$branch${reset_color}"
        fi
    fi

    # Virtualenv
    local venv_prompt=
    if [ -n "$VIRTUAL_ENV" ]; then
        venv_prompt=" ${blue}$prompt_venv_symbol$(basename $VIRTUAL_ENV)${reset_color}"
    fi

    # Only show username if not default
    local user_prompt=
    [ "$USER" != "$local_username" ] && user_prompt="$user_color$USER${reset_color}"

    # Show hostname inside SSH session
    local host_prompt=
    [ -n "$remote" ] && host_prompt="@${yellow}$HOSTNAME${reset_color}"

    # Show delimiter if user or host visible
    local login_delimiter=
    [ -n "$user_prompt" ] || [ -n "$host_prompt" ] && login_delimiter=":"

    # Format prompt
    first_line="$user_prompt$host_prompt$login_delimiter${white}\w${reset_color}$git_prompt$venv_prompt"
    # Text (commands) inside \[...\] does not impact line length calculation which fixes stange bug when looking through the history
    # $? is a status of last command, should be processed every time prompt prints
    second_line="\`if [ \$? = 0 ]; then echo \[\$CYAN\]; else echo \[\$RED\]; fi\`\$prompt_symbol\[\$NOCOLOR\] "
    PS1="\n$first_line\n$second_line"

    # Multiline command
    PS2="\[$CYAN\]$prompt_symbol\[$NOCOLOR\] "

    # Terminal title
    local title="$(basename "$PWD")"
    [ -n "$remote" ] && title="$title \xE2\x80\x94 $HOSTNAME"
    echo -ne "\033]0;$title"; echo -ne "\007"
}

# Show awesome prompt only if Git is istalled
command -v git >/dev/null 2>&1 && PROMPT_COMMAND=prompt_command