This guide will show you step-by-step how to requeue emails in Postfix on Linux. I've been using these steps on my Debian and Ubuntu mail servers, but they should work on other Linux distributions like CentOS, Rocky Linux and AlmaLinux too. Requeue Email in Postfix Access the Linux System: Log in to the Linux system ... Read more
Using the tcpserver program on Linux is not deprecated. Tcpserver is a utility included in the ucspi-tcp package that listens for connections from TCP clients and, for each connection, executes a specified program. This tool is particularly useful for setting up simple TCP services, where each incoming connection triggers the execution of a program, script, ... Read more
Using xinetd (Extended Internet Service Daemon) on Linux is not deprecated, but its usage and relevance have evolved over time. Xinetd is an open-source super-server daemon that runs on many Unix-like systems, managing Internet-based connectivity. It is a more secure and feature-rich alternative to the older inetd ("Internet daemon"), which has been deprecated by most ... Read more
In this example, I will use the getent command to check if a Linux group exists. if getent group "$groupname" >/dev/null; then echo "Group $groupname exists" fi Replace $groupname with the name of the group you want to check. If you like to check if the group does not exist (e.g. because you like to ... Read more
Here I will show you how to check if a Linux user exists (or does not exist) in a POSIX-compatible shell like Bash or Dash. I will use the getent command along with the /etc/passwd file for this. Example Bash script: if getent passwd "$username" >/dev/null; then echo "User $username exists" else echo "User $username ... Read more
The bash history is a log file that contains all commands that a user executed on the Linux BASH shell. When you use the "arrow up" key on your keyboard, then Bash will look up the previous command from that file and display it on the screen. You just have to press "Enter" to execute ... Read more
Bash shell refers to Bourne Again Shell which can be found as the default shell in most of the Linux distributions. A Bash Script is a file where multiple shell commands are scripted to perform a particular task. If you are familiar with bash script then this article is for you, in this demonstration I ... Read more
To restart a CentOS system, you can use both the command line (shell) and the desktop environment (GUI). Using the Command Line (Shell) to restart CentOS Open a terminal: You can open a terminal in CentOS by pressing `Ctrl+Alt+T` or by searching for "Terminal" in the application menu. Alternatively, connect to the system using SSH ... Read more
When using a custom docroot in the custom Apache directives field in ISPConfig, the /stats folder becomes inaccessible. An easy way to make it accessible again is by using an alias. Add the following Apache directives into the custom directives field of the website in ISPConfig: Alias "/stats" "{DOCROOT_CLIENT}/stats" Thanks to Thom for providing the ... Read more
NFS (Network File System) is a distributed file system protocol developed by Sun Microsystems to share files and folders between Linux/Unix systems. NFS allows us to mount the file system over the local network. NFS uses standard client/server architecture for sharing files and directories between Linux-based systems. This tutorial will help you to set up ... Read more