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Shell Redirection: >, >>, <, |, 2> and tee Explained

Bash

Methods for redirecting data through the shell, either from/to files or commands. Standard Input...

Updated 5 months ago by Daniel

Hard & Symbolic Links

Bash

The ln command is used to create links between files. There are two types of links: HardLinks & S...

Updated 5 months ago by Daniel

GREP

Bash

GREP Grep is used to search file contents for a particular string or pattern. grep [option] {se...

Updated 5 months ago by Daniel

Data Manipulation: echo, printf, tr, wc, sort, cut, paste, diff, awk, sed

Bash

echo Built-in Linux feature to print out arguments as standard output. echo {string} print...

Updated 5 months ago by Daniel

Find & Locate

Bash

FIND Find is a linux search tool that can be used to find a variety of files based on the give...

Updated 5 months ago by Daniel

VI/VIM

Bash

VIM is the best Linux text editor. i insert. A insert at the end of the current l...

Updated 5 months ago by Daniel

LogRotate

Logging

LogRotate Configuration. https://www.redhat.com/sysadmin/setting-logrotate If not installed alr...

Updated 5 months ago by Daniel

initrd (initialisation RAM disk)

Boot, Kernel, Recovery, and Tunables

What are initramfs and initrd? initrd and initramfs are temporary root filesystems loaded into...

Updated 5 months ago by Daniel

Kernel Tuneable's

Boot, Kernel, Recovery, and Tunables

Kernel Tunables In Linux, a tunable refers to a specific type of configuration setting within th...

Updated 5 months ago by Daniel

Kernel Modules

Boot, Kernel, Recovery, and Tunables

What is a kernel module? A kernel module is essentially a piece of code that can be loaded int...

Updated 5 months ago by Daniel

Single User Mode

Boot, Kernel, Recovery, and Tunables

Boot the server into 'single user mode' B. Once in single user mode, we can look to initiate t...

Updated 5 months ago by Daniel

LDAP (Lightweight Directory Access Protocol)

SSH & Authentication

LDAP (Lightweight Directory Access Protocol) is a protocol used to access and manage directory se...

Updated 5 months ago by Daniel

Troubleshooting Boot Issues & System Recovery

Boot, Kernel, Recovery, and Tunables

System boot logs The below log files are most relevant to viewing boot logs and errors dmesg ...

Updated 5 months ago by Daniel

Linux Boot Process

Boot, Kernel, Recovery, and Tunables

The below image outlines the typical flow of a Linux system boot. 1. BIOS (Basic Input/Outpu...

Updated 5 months ago by Daniel

LBv2 Overview

LoadBalancers

ANS Portal > Servers > Load Balancers Services: haproxy   Warden  /var/log/warden/warden.log  ...

Updated 5 months ago by Daniel

File Permissions & Ownership

User Management & File Permissions

Linux File Ownership Files and directories in Linux are owned by a user and a group. chown The...

Updated 5 months ago by Daniel

Sandboxing & CHROOT

Software & Service Management

==================================================================================== CHROOT (Cha...

Updated 5 months ago by Daniel

ARP

System Networking

show arp cache arp -a 

Updated 5 months ago by Daniel

Auto Restart Services

Software & Service Management

https://www.redhat.com/sysadmin/systemd-automate-recovery  1) Edit elasticsearch service unit ...

Updated 5 months ago by Daniel

Single User Mode

Boot, Kernel, Recovery, and Tunables

==================================================================================== You might n...

Updated 5 months ago by Daniel