CentOS Archives

Get the name of the newest file in a directory on the linux shell

June 21, 2021June 21, 2021 by Till Brehm

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

Reduce CPU and Disk load of backup scripts with nice and ionice

June 9, 2021June 9, 2021 by Till Brehm

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

[Solved] system-config-firewall: command not found

May 11, 2021May 11, 2021 by Till Brehm

When you get the error message "system-config-firewall: command not found" on your CentOS Server while trying to configure the firewall on the shell, then the text interface version of the firewall configuration utility is missing. Install CentOS Firewall configuration tool Install it with this command: yum install system-config-firewall-tui

How to change the Hostname on CentOS 8

May 4, 2021May 4, 2021 by Till Brehm

The easiest way to change the hostname on CentOS 8 is to use the hostnamectl command. First I will check the current hostname by running "hostnamectl status" on the shell of my server: hostnamectl status The output on my system is: [[email protected] ~]# hostnamectl status Static hostname: server1.example.com Icon name: computer-vm Chassis: vm Machine ID: ... Read more

How to add PHP support for jailed SSH users in ISPConfig 3

April 23, 2021April 23, 2021 by Till Brehm

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

How to clear Bash history on Linux

April 23, 2021April 23, 2021 by Till Brehm

The bash history is a log file that contains all commands that the user executed on the Linux shell. When you use the "arrow up" key on our keyboard, then Bash will look up the previous command from that file and display it on the screen, ready to be executed again. Bash history file location The ... Read more

Disable IPv6 networking on CentOS

by Till Brehm

Follow these steps to disable IPv6 on CentOS. Edit the /etc/sysctl.conf file, I will use the nano editor here: nano /etc/sysctl.conf And add the following line at the end of the file: net.ipv6.conf.all.disable_ipv6 = 1 Then run: sysctl -p to load the new settings. The next step is to edit the network card configuration file (/etc/sysconfig/network-scripts/ifcfg-eth*) ... Read more

How to Backup OpenVZ Containers with vzdump on CentOS 6

by Till Brehm

OpenVZ is a Linux based Kernel virtualization technology developed by SWSoft for its commercial product Virtuozzo. The modified Linux Kernel and the system utilities are released under an OpenSource license. Vzdump is a shell based backup program for OpenVZ virtual machines. It is made for containers that use the traditional "simfs" filesystem, it can not be used for containers with "ploop" filesystem.

How to use IPTables on CentOS 7

by Till Brehm

Centos 7 replaced the traditional IPTables Linux Kernel Firewall with the Firewalld service. There are still a lot of scripts available that require the use of IPTables. A common example is the software Fail2ban. In this guide, I will explain the installation of IPTables on Centos 7.x The first step is to stop and mask ... Read more

How to Copy Files with SCP between Linux Servers

by Till Brehm

1.1 SCP Command Line-An Overview

The SCP command line is commonly used to copy files over SSH, and between popular Operating systems like Linux, Mac and Windows in a secure fashion. SCP is used to copy files to/from a remote server. It also allows you to copy files from one remote server to another remote server, without passing traffic through your PC.