docker-mailserver/target/bin/addmailuser

#!/bin/bash

DATABASE=/tmp/docker-mailserver/postfix-accounts.cf

function usage {
 echo 'Usage: addmailuser <user@domain.tld> [password]'
 exit 1
}

if [ ! -z "$1" ]; then
 USER=$1
 if [ -e "$DATABASE" ] && [ ! -z "$(grep $USER -i $DATABASE)" ]; then
  echo "User already exists"
  exit 1
 fi
 if [ ! -z "$2" ]; then
  PASS="$2"
 else
  read -s -p "Enter Password: " PASS
  if [ -z "$PASS" ]; then 
   echo "Password can't be empty"
   exit 1
  fi
 fi
 ENTRY=$(echo "$USER|$(doveadm pw -s SHA512-CRYPT -u "$USER" -p "$PASS")")
 echo "$ENTRY" >> $DATABASE
else
 usage
fi