Add/Modify Users

Operating systems have never provided a unified method of managing local user accounts. Every platform provides a unique interface for adding or modifying user accounts, and this has frequently been used as justification for abstracting all systems related changes using traditional configuration management tools.

A helper script for manage local users solves this problem by defining a single function that will add a user if it doesn't exist, or update an existing user if it is already defined.

OpenBSD

The calling convention employed in this function is specify positional arguments followed by arguments that are only applicable to useradd(8). Remaining arguments are appended to add or modify conditions.

function userset {
    # args: username [useradd args ...] [usermod args ...]
    username=$1
    shift

    if ! userinfo -e $username; then
        useradd "$@" $username
    else
        # knock off parameters that do not apply
        while [ $# -gt 1 ]; do
            case $1 in
                -m) shift ;;
                 *) break ;;
            esac
            usermod "$@" $username
        done
    fi
}

Examples:

userset eradman -u 1000 -G wheel,operator,wsrc,staff,dialer -c "Eric Radman"
userset unlockwww -u 1003 -g 10 -c "AuthPF" -s /usr/sbin/authpf

GNU/Linux

Similar to the OpenBSD implementation, but detection of an existing user using id(1)

userset() {
    # args: username [useradd args ...] [usermod args ...]
    username=$1
    shift

    if ! id $username > /dev/null; then
        useradd "$@" $username
    else
        # knock off parameters that do not apply
        while [ $# -gt 1 ]; do
            case $1 in
                -m) shift ;;
                 *) break ;;
            esac
            usermod "$@" $username > /dev/null
        done
    fi
}

Examples:

userset laura -m -u 1004 -g 1004 -s /bin/bash
userset abigail -m -u 1006 -g 1006 -s /bin/bash

FreeBSD

On FreeBSD all system user commands are wrapped by pw(8) and the username is at the beginning rather than the end.

userset() {
    # args: username [useradd args ...] [usermod args ...]

    username=$1
    shift

    if ! pw usershow $username 2>/dev/null 1>/dev/null; then
        pw useradd $username "$@"
    else
        # knock off parameters that do not apply
        while [ $# -gt 1 ]; do
            case $1 in
                -m) shift ;;
                 *) break ;;
            esac
            pw usermod $username "$@"
        done
    fi
}

Examples:

userset abigail -m -u 1006 -G guest -c "Abigail"