Apache Invalid command AuthGroupFile

On Plesk server, i get following error on error_log for a site

This is because authz_groupfile apache module was not loaded. To load this, run

To verify the module is loaded, run

Linux How to Disable a user account

To disable or lock a linux user account, run


To verify if a user is locked, run

If account is disabled/locked, it will show L.

WordPress debug

If you have a wordpress web site that give blank screen, you can add following to wp-config.php to enable displaying errors.

This should be added above line

Apache Limit access to a url

I want to limit access to admin login url of a web application to specified IP address.

The web site had admin login in following URL


To limit IP address, i edited Apache VirtualHost configuration for this web site, added

Restart apache


Now only IP listed on the Allow from directive are allowed to access the /login URL.

NOTE: this won’t work in .htaccess file. You need to add it in Apache VirtualHost.

Plesk License Number

Install PHP 5.6 on Debian 9 Plesk Server

To install PHP 5.6 on Debian 9 Plesk Server, add sury.org repository

Install PHP 5.6 with apt

Optional: Enable PHP 5.6 as default CLI

This will show all available PHP version, select the default version for command line.

Enable PHP 5.6 in Plesk


Install LetsEncrypt SSL on Gitlab

To enable LetsEncrypt free SSL on Gitlab, edit file

Modify following configrations

external_url should start with HTTPS.

Run command

Now gitlab installation will work with HTTPS.


crontab command is used to list/editc cronjobs.

To list all cronjobs for current user, run

To edit cronjob for current user, run

To edit for a specific user, you can use

To list cronobs for a specific user, you can use

See cronjob