#!/usr/bin/env bash
users=$(for s in /home/*; do echo "${s##*/}"; done)
subuid_start=100000
incr=65536
for user in ${users[@]}; do
    uid=$(id -u "$user")
    echo "$user:$subuid_start:$incr" >> /etc/subuid
    echo "$user:$subuid_start:$incr" >> /etc/subgid
    subuid_start=$((subuid_start + 100000))
done