Show git branch on bash prompt

.bashrc

## My alias
# mkpass - Generate random string with 12 chars
alias mkpass='python -c "import random, string; print \"\".join(random.choice(string.ascii_letters + string.digits + \"[]\") for x in range(12))"'


## Virtualenvwrapper Settings
VIRTUALENVWRAPPER=`which virtualenvwrapper.sh`
export WORKON_HOME=$HOME/.virtualenvs

if [ -f ${VIRTUALENVWRAPPER} ]; then
    source ${VIRTUALENVWRAPPER}
fi

## PIP Settings
export PIP_DOWNLOAD_CACHE=$HOME/.pip_download_cache/

## Print the current branch if current dir is a git repo.
function git_branch {
    if git ls-files >& /dev/null; then
        branch_name="`git branch | grep '*'`"
    
        if [ -z "$branch_name" ]; then
            branch_name="no_branch"
        fi

        echo " [git:${branch_name//[*\ ]/}]"
    fi
}

## Shell settings
export PS1='\[\e[00;37m\]`git_branch`\[\e[0m\]\[\033[0;36m\] \w - \u\$\[\e[0m\] '