create-daemon-user

create-daemon-user.bash

#!/usr/bin/env bash

# Make sure we are root
if [[ $EUID -ne 0 ]]; then
    echo "This script must be run as root" 1>&2
    exit 1
fi

if [ -z "$1" ]; then
    echo "Provide the user name as the first argument." 1>&2
    exit 1
fi

get_next_daemon_uid() {
    all_uids=$(dscl . -list /Users UniqueID | grep -o '[0-9]\+' | sort -nr)
    for uid in $all_uids; do
        if (( uid < 500 )); then
           echo "$((( uid + 1 )))"
           exit 0
        fi
    done
    exit 1
}

next_uid=$(get_next_daemon_uid)

username="$1"
realname="${1} daemon"

echo "Creating group _${username} with gid: ${next_uid}"

dscl . -create "/Groups/_${username}"
dscl . -create "/Groups/_${username}" PrimaryGroupID "$next_uid"
dscl . -create "/Groups/_${username}" RecordName "_${username}" "$username"
dscl . -create "/Groups/_${username}" RealName "$realname"
dscl . -create "/Groups/_${username}" Password \*

echo "Creating user _${username} with uid: ${next_uid}"

dscl . -create "/Users/_$username"
dscl . -create "/Users/_$username" NFSHomeDirectory /var/empty
dscl . -create "/Users/_$username" Password \*
dscl . -create "/Users/_$username" PrimaryGroupID "$next_uid"
dscl . -create "/Users/_$username" RealName "$realname"
dscl . -create "/Users/_$username" RecordName "_${username}" "$username"
dscl . -create "/Users/_$username" UniqueID "$next_uid"
dscl . -create "/Users/_$username" UserShell /usr/bin/false
dscl . -delete "/Users/_$username" PasswordPolicyOptions
dscl . -delete "/Users/_$username" AuthenticationAuthority