control-o.bash

# A handy j() function, printing some useful info in bash cmdline
j() {
    printf '\n\e[0;35m%(%Y/%m/%d (%a) %H:%M:%S)T\e[0m ' -1
    printf '\n\e[0;33m%s@%s\e[0m ' "$USER" "${HOSTNAME/.*/}"

    if git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
        local GIT_CLEAN=
        local GIT_REF=$(git rev-parse --abbrev-ref HEAD 2>/dev/null)
        git diff-index --quiet HEAD && GIT_CLEAN=1

        if [ "$GIT_CLEAN" ]; then
            printf '\e[0;32mgit:%s(clean) ' "$GIT_REF"
        else
            printf '\e[0;31mgit:%s(dirty) ' "$GIT_REF"
        fi
    fi

    printf '\e[0;34m'
} # end of function j()

# Simple bash prompt
PS1='$PWD \$ \[\033[0m\]'

# Enable Control-O in readline bash
stty discard undef

# Bind Control-O to execute my j() bash function
bind -x '"\C-o": j'

What is it?

This is just a simple illustration of the idea about how you can keep your bash prompt simple (and fast), and get more information only when you need some.

Demo

(I pressed Ctrl-O just before each colored prompt shows up)

Normally, the bash cmdline prompt is just the working directory name followed by a '$' character.

When I want to know more about what's going on, I press Control-O, and then the powerful colored prompt with customized information will show up as shown in the above image. You can change the j() function to meet your needs.

FYI, I am using GNU bash version 4.2.45 (installed by Homebrew) on OS X for this demo.