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CentOS

LINUX – nmcli command examples (cheatsheet), compare nm-settings with if-cfg file

Table of Contents Understanding nmcli Compare nm-settings with ifcfg-* directives (IPv4) Compare nm-settings with ifcfg-* directives (IPv6) Brief list of nmcli commands syntax nmcli command examples (cheatsheet) 1. Check if…
CentOS

CentOS – Installer just goes black screen on Centos8

Problem: During installation of CentOS the installer screen goes black. The terminal multiplexer is running in virtual console 1. To switch from the graphical installation environment to tmux, press Ctrl+Alt+F1. To go back to the main…

How to force fsck at every boot in Linux

In /etc/init.d/checkfs.sh is the line if [ -f /forcefsck ] || grep -s -w -i "forcefsck" /proc/cmdline, so providing forcefsck on the kernel command line or generating a /forcefsck file on shutdown should cause an fsck on the next reboot. To…
CentOS

LINUX – Network Throughput Tuning

General Approach To check what setting your system is using, use 'sysctl name' (e.g.: 'sysctl net.ipv4.tcp_rmem'). To change a setting use 'sysctl -w'. To make the setting permanent add the setting to the file 'sysctl.conf'. [crayon-6872487da93d3164381444/] More…
CentOS

CentOS – How do I safely delete old kernel versions ?

package-cleanup: Using package-cleanup command which is a part of yum-utils package we can uninstall any number of old kernels automatically. As an example using --oldkernels --count=2 option with package-cleanup command the command…

CentOS – NIC Teaming with LACP

A Comparison of Features in Bonding and Team Feature Bonding Team broadcast Tx policy Yes Yes round-robin Tx policy Yes Yes active-backup Tx policy Yes Yes LACP (802.3ad) support Yes (active only) Yes Hash-based…

Linux – iproute2 Cheat Sheet

Overview iproute2 is the Linux networking toolkit that replaced net-tools (ifconfig, route, arp etc.) Old style network utilities like ifconfig and route are still there just for backwards compatibility and do not provide access to…
Linux File Permissions

Linux – Permissions

  In order to update and change file permissions, you can use the chmod command. The format of the command is as follows: [crayon-6872487dace63716401911/] for each action   Changing Permissions VALUE MEANING rwx+ugo No…

How to Disable or Enable Disk Write Caching in Linux

ATA-Based Disks Check out whether disk caching is enabled on your disk or not: [crayon-6872487dad2c1196177101/] To disable write caching, you need to edit hdparm.conf using your favorite editor (e.g. gedit, vi). [crayon-6872487dad2c9617188961/] …