docker-mailserver/target/bin/updatemailuser

#! /bin/bash

DATABASE=${DATABASE:-/tmp/docker-mailserver/postfix-accounts.cf}

USER="$1"
PASSWD="$(doveadm pw -s SHA512-CRYPT -u "$USER" -p "$2")"

usage() {
	echo "Usage: updatemailuser <user@domain.tld> [password]"
}

errex() {
	echo "$@" 1>&2
	exit 1
}

escape() {
	echo "${1//./\\.}"
}

[ -z "$USER" ] && { usage; errex "no username specified"; }

grep -qi "^$(escape "$USER")|" $DATABASE 2>/dev/null ||
	errex "User \"$USER\" does not exist"
sed -i "s ^"$USER"|.* "$USER"|"$PASSWD" " $DATABASE