glum - Git Lightweight User Management

glum.sh

#!/bin/bash
# Git Lightweight User Management

# To start a new user 'session'
#   glum USER EMAIL
# To end user 'session'
#   glum

glum-broken() {
    # This shows an error, and replaces git in the current shell as an alias to this function
    echo "[ git glum: ERROR, set git user with 'glum USER EMAIL' ]" >&2
    rm -f /tmp/glum.lock
    return 1
}
glum-info() {
    echo "[ git glum: $(git config --global user.name) <$(git config --global user.email) ]"
}

glum() {
    git config --global user.name > /dev/null && git config --global --remove-section user
    if test $# -eq 0
    then
        glum-broken || :
        export PS1='\u@\h:\w$ '
        alias git='glum-broken'
    elif test $# -eq 2
    then
        git config --global user.name "$1"
        git config --global user.email "$2"
        unalias git
        touch /tmp/glum.lock
    else
        echo "Usage:"
        echo "  glum USER EMAIL     Sets current user"
        echo "  glum                Removes current user"
    fi
}

if ! test -e /tmp/glum.lock
then
    glum
else
    glum-info
fi