Alters bash to make working with Git in the shell easier. Will set the current repository and branch name in the prompt and makes `g` an alias to `git`.

git_bash_prompt.sh

#!/bin/bash

_git_has_commits() {

    if git rev-parse --verify HEAD > /dev/null 2>&1; then
        return 0
    else
        return 1
    fi

}

_git_current_branch_name() {

    if _git_has_commits ; then
        git rev-parse --short --abbrev-ref HEAD
    else
        echo "master"
    fi

}

_git_current_remote() {

    remote=$(git config --get branch.$(_git_current_branch_name).remote)

    if [[ -z "$remote" ]]; then
        remote=origin
    fi

    echo $remote

}

_git_current_remote_branch_name() {
    git config --get branch.$(_git_current_branch_name).merge | sed 's/[a-z]\+\/[a-z]\+\///g'
}

_git_current_remote_url() {
    git config --get remote.$(_git_current_remote).url
}

_git_current_repos_name() {

    if _git_has_commits ; then
        _git_current_remote_url | sed 's/^.*\/\(..*\)\.git/\1/'
    else
        echo "unknown"
    fi

}

_git_state() {

    if _git_has_commits ; then

        if ! git diff --quiet 2> /dev/null ; then
            echo "not-staged"
        elif ! git diff --staged --quiet 2> /dev/null ; then
            echo "not-committed"
        elif ! git diff $(_git_current_remote)/$(_git_current_remote_branch_name) --quiet 2> /dev/null ; then
            echo "not-pushed"
        elif [[ -n "$(git log $(_git_current_remote)/$(_git_current_remote_branch_name)..$(_git_current_branch_name))" ]] ; then
            echo "diverged"
        else
            echo "clean"
        fi

    else
        echo "not-initialized"
    fi

}

_git_activate_branch_color() {

    state=$(_git_state)

    if [[ $state == "not-initialized" ]] ; then
        tput setaf 7 # grey
    elif [[ $state == "not-staged" ]] ; then
        tput setaf 1 # red
    elif [[ $state == "not-committed" ]] ; then
        tput setaf 3 # yellow
    elif [[ $state == "not-pushed" ]] ; then
        tput setaf 6 # blue
    elif [[ $state == "diverged" ]] ; then
        tput setaf 5 # purple
    else
        tput setaf 2 # green
    fi

}

_git_stash_indicator() {

    stash_count=$(git stash list | wc -l | sed 's/ //g')

    if [[ $stash_count -gt 0 ]] ; then
        echo " - $(tput setaf 1)$stash_count$(tput setaf 4)"
    fi

}

_git_weblink() {

    link_start=https://$(git remote get-url origin | cut -d '@' -f 2 | sed 's/:/\//g' | cut -d '.' -f 1,2)
    commit_hash=$(git log -1 --format='%H')

    if [[ -n "$1" ]]; then
        echo "$link_start"/tree/"$commit_hash"/$(git ls-tree --full-name --name-only $commit_hash $(echo "$1" | sed 's/\/$//'))
    else
        echo "$link_start"/commit/"$commit_hash"/
    fi

}

# The `\` before the `$` in `\$(func_name)` will make the `func_name`
# function execute every time the prompt is printed.
export PS1="\
\[$(tput bold)\]\
\[$(tput setaf 4)\]\
git [\
\[$(tput setaf 2)\]\$(_git_current_repos_name)\[$(tput setaf 4)\] - \
\[\$(_git_activate_branch_color)\]\$(_git_current_branch_name)\[$(tput setaf 4)\]\
\$(_git_stash_indicator)\
] \$ \[$(tput sgr0)\]\
"

# Short alias for git stuff
alias g=git

# Make autocomplete also work fo the `g` alias
eval $(complete -p git | sed 's/git$/g/g')