How to Fix “firewall-cmd: command not found” Error in RHEL/CentOS 7
firewall-cmd is a command line front-end for firewalld (firewalld daemon), a dynamic firewall management tool with D-Bus interface. It supports both IPv4 and IPv6; it
How to Make File and Directory Undeletable, Even By Root in Linux
On Unix-like operating systems including Linux, root is the account or user name that by default can modify all directories and files on a system.
How To Protect Hard and Symbolic Links in CentOS/RHEL 7
In Linux, hard and soft links are referenced to files, which are very important, if not protected very well, any vulnerabilities in them can be
10 Strace Commands for Troubleshooting and Debugging Linux Processes
strace is a powerful command line tool for debugging and trouble shooting programs in Unix-like operating systems such as Linux. It captures and records all
How to Create Hard and Symbolic Links in Linux
In Unix-like operating systems such as Linux, “everything is a file” and a file is fundamentally a link to an inode (a data structure that
How to Recover or Rescue Corrupted Grub Boot Loader in CentOS 7
In this tutorial we’ll cover the process of rescuing a corrupted boot loader in CentOS 7 or Red Hat Enterprise Linux 7 and recover the
How to Install PHP 7.3 in CentOS 7
The CentOS 7 official software repositories have PHP 5.4 which has reached the end of life and no longer actively maintained by the developers. To
Install a Complete Mail Server with Postfix and Webmail in Debian 9
This tutorial will guide you on how to install and configure a complete mail server with Postfix in Debian 9 release. It will also cover
How to Install PHP 7 in CentOS 6
The CentOS 6 official software repositories has PHP 5.3 which has reached end of life and no longer actively maintained by the developers. To keep
How to Disconnect Inactive or Idle SSH Connections in Linux
In our previous article, where we’ve explained how to TMOUT shell variable to auto logout Linux shell when there isn’t any activity. In this article,
Initial Server Setup and Configurations on CentOS 7
This tutorial will explain the first basic steps you need to go through after installing a minimal CentOS 7 system with no graphical environment in
TMOUT – Auto Logout Linux Shell When There Isn’t Any Activity
How often do you leave a Linux system idle after login; a situation which can be referred to as an ‘idle session’, where you are