#! /bin/sh -

set -eu

if [ -z "$1" ] || ! expr -- "$1" : "[0-9][0-9]*" >/dev/null; then
	echo "Usage: $0 NUMBER" 2>/dev/null
	exit 1
fi

if [ "$1" -lt 1 ]; then
	echo "ERROR: NUMBER should be at least 1" 2>/dev/null
	exit 1
fi

for n in $(seq 1 "$1"); do
	user="nixbld${n}"
	if pw usershow "$user" >/dev/null 2>&1; then
		continue
	fi
	pw useradd "$user" -c "Nix build user $n" -d /var/empty -G nixbld \
		-g nixbld -s /usr/sbin/nologin
done