My .bashrc: complete with colored prompt, virtualenv support, and github support.

.bashrc

set_prompt () {
    if venv_file=$(find-venv); then
        source $venv_file
    elif [ "$(type -t deactivate)" == "function" ]; then
	deactivate
    fi
    PS1=$(append-git-branch)
}

GREY="\[\e[1;30m\]"
BLUE="\[\e[1;34m\]"
GREEN="\[\e[1;32m\]"
DEFAULT="\[\e[0m\]"

export CLICOLOR=1
export PS1="${GREY}\h${DEFAULT}:${GREEN}\w ${BLUE}\u${DEFAULT}$ "
export PATH=$PATH:$HOME/bin
# export PATH=$PATH:$HOME/bin:$HOME/go-ethereum/build/bin
export PROMPT_COMMAND=set_prompt

alias ls="ls -Fa"
alias ll="ls -Fal"
# alias geth="geth --fast --cache 4096"
# alias geth-console="geth attach"

append-git-branch

#!/usr/bin/python
# make sure to `chmod +x` this and put it somewhere in your path!
import subprocess
from subprocess import CalledProcessError
import os
import re

DEVNULL = open(os.devnull, 'w')
BRANCH = re.compile('^.+? \((.+)\) .+\$ $')


def get_current_branch():
    try:
        result = subprocess.check_output(['git', 'branch'], universal_newlines=True, stderr=DEVNULL)
    except CalledProcessError:
        return None

    for line in result.strip().split('\n'):
        if line.startswith('* '):
            return line.lstrip('* ')

    return None


def main():
    PS1 = os.environ['PS1']
    branch = get_current_branch()
    match = BRANCH.match(PS1)
    if branch and match:
        print PS1[:match.start(1)] + branch + PS1[match.end(1):]
    elif branch and (match is None):
        parts = PS1.rsplit(' ', 2)
        parts[0] += ' ({})'.format(branch)
        print ' '.join(parts)
    elif (branch is None) and match:
        print PS1[:match.start(1)-2] + PS1[match.end(1)+1:]
    else:
        print PS1

if __name__ == '__main__':
    main()

find-venv

#!/usr/bin/python
# make sure you `chmod +x` this and put it somewhere in your path!
import os


def check_path(path):
    """Checks if a path is a virtualenv."""
    return os.path.isfile(os.path.join(path, 'bin', 'activate'))


def find_venv():
    """Searches for a virtualenv in the current path or it's parents."""
    search_path = os.getcwd()
    while not check_path(search_path):
        new_search_path = os.path.dirname(search_path)
        if new_search_path == search_path:
            return None
        search_path  = new_search_path
    return search_path


def main():
    result = find_venv()
    if result is None:
        return 1
    else:
        print(os.path.join(result, 'bin', 'activate'))
        return 0

if __name__ == '__main__':
    import sys
    sys.exit(main())