The shell setting in /etc/passwd determines whether a Linux system user may log in via the shell or over SSH. If you don't want a certain user to be able to log in, set the shell to /bin/false or /sbin/nologin. For the user "otheruser" on Debian and Ubuntu Linux, here's an example: usermod -s /bin/false ... Read more
Have you ever looked in the apache config files to see where a website's virtual host is defined? The apache2ctl script has a useful option that could come in good here. When you execute the command, it should look like this: apache2ctl -S You'll obtain a list of all virtual hosts and default servers in ... Read more
Sometimes you require a certain file from a Debian .deb package. For example, because you accidentally deleted a file. Or because the package's installation is faulty and it can't be restored without first adding the missing file. This FAQ explains how to extract the contents of a.deb file downloaded from the Debian or Ubuntu repository. ... Read more
If you have a directory with many files (a few thousand in my case) and need to know which one is the newest, then the following command might be useful. It returns the name and details of the newest file in a directory where it is executed: ls -tl | sed -n 2p
Running a nightly backup script on a server system, such as a web hosting server, can result in a heavy load and longer latency for other processes, for example, HTML or .php pages load slowly during the backup because the backup script requires too many I/O or CPU resources. On Linux systems, two shell utilities ... Read more
In this short article, I explain how to disable IPv6 in the Debian 10 network stack. Why would one want to do this? Most likely if you have connection problems and cannot reach servers on the Internet from your Debian system using IPv6, while it works using IPv4. Disabling IPv6 should always be the last ... Read more
The following command can be used to check and repair all MySQL databases on a Ubuntu or Debian Linux System. I've tested the commands on Ubuntu 20.04 and Debian 10. Repair MySQL databases on Ubuntu Linux sudo mysqlcheck --defaults-file=/etc/mysql/debian.cnf --auto-repair --optimize --all-databases MySQL database repair on Debian mysqlcheck --defaults-file=/etc/mysql/debian.cnf --auto-repair --optimize --all-databases The benefit of ... Read more
This short tutorial describes the steps to optimize the performance of a MySQL database with the mysqltuner script. This tool can be used for MySQL and MariaDB. Install mysqltuner The mysqltuner High-Performance MySQL Tuning Script is available as a package on Debian 10 and Ubuntu 20.04, install it with at: sudo apt install mysqltuner For ... Read more
This short guide shows you how to get a list of all installed Packages on Debian Linux. Packages on Debian get installed with the apt package installer. We will use the dpkg command, which is part of the apt toolset, to query the installed packages database. Get all installed Debian packages dpkg --get-selections As you ... Read more
Jailkit is an easy-to-use tool to create and maintain jail environments for shell users on Linux. In this guide, I will show you how to move PHP and its dependencies into the jail so that the jailed user can execute PHP scripts inside the jail on an ISPConfig server. Edit the jailkit .ini file and ... Read more