docker-mailserver/target/bin/delmailuser

#!/bin/bash

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

function usage {
  echo "Usage: delmailuser <user@domain.tld>"
   exit 1
}

if [ ! -z "$1" ]; then
  USER=$1
  if [ -f "$DATABASE" ]; then
    ENTRIES=$(grep "$USER" -vi $DATABASE)
    echo "$ENTRIES" > $DATABASE
  fi
else
  usage
fi