usermod Cheatsheet

Quick reference for modifying Linux user accounts with usermod and managing groups with groupadd, gpasswd, and groupdel

Apache Cheatsheet

Apache HTTP Server at a glance: service commands, file layout on Ubuntu and RHEL, virtual hosts, modules, .htaccess, redirects, TLS, reverse proxy, and log …

SSH Config Cheatsheet

SSH client config directives at a glance: Host and Match patterns, keys, jump hosts, keepalives, multiplexing, port forwarding, host key checking, and tokens …

How to Resize and Extend a Linux Partition and Filesystem

Extend a Linux partition and grow ext4, XFS, Btrfs, or LVM storage after a disk resize, with layout checks, safe ext4 shrink steps, and troubleshooting.

sudo Cheatsheet

sudo at a glance: running commands as root, credential caching, environment handling, sudoers rule syntax, aliases, Defaults, and logging.

ffmpeg Cheatsheet

Keep essential ffmpeg commands close at hand, from stream inspection and lossless remuxing to CRF encoding, filters, subtitles, and GPU acceleration.

Chapter 1: Why Tmux? Understanding Terminal Multiplexing

If you have ever run a long command over SSH and lost it because your connection dropped, you already understand the pain tmux solves. Tmux is a terminal multiplexer. In plain language, it lets you run and manage multiple terminal workspaces inside one terminal environment, and…

Feature comparison of ack, ag, git-grep, grep and ripgrep

DNS Record Types Explained: A, AAAA, CNAME, MX, TXT, and More

DNS record types map domains to servers, route email, publish verification data, and control certificate issuance. See zone-file examples and dig queries.

DNS record cards linking a domain to IP addresses, mail servers, and security policies

MX records route email

lsblk Command in Linux: List Block Devices

Use lsblk to list disks, partitions, filesystems, UUIDs, and mount points in Linux, then customize columns and produce JSON output for scripts.

How to Tail and Filter Logs in Real Time on Linux

Follow Linux logs in real time with tail -F, filter live output with grep, pause with less +F, and stream systemd service logs with journalctl -f.

How to Install and Configure the AWS CLI on Linux

Install AWS CLI version 2 on Linux, authenticate with aws login or IAM Identity Center, manage profiles, and verify access to your AWS account.

How to Convert MP4 to MP3 with ffmpeg

Convert MP4 video to MP3 audio from the Linux command line with ffmpeg, including quality settings, lossless extraction, trimming, and batch conversion.

How to Find Which Process Is Using a Port in Linux

Find the Linux process listening on a TCP or UDP port with ss, lsof, fuser, or netstat, then inspect and stop it safely.

mount Cheatsheet

Quick reference for the mount command: mount and unmount filesystems, mount options, UUID and label mounts, network shares, and /etc/fstab entries

lsusb, lspci, and lshw: List Hardware in Linux

Identify the hardware in a Linux machine: list USB devices with lsusb, find PCI cards and their drivers with lspci, and get a full inventory with lshw.

What Is an Inode in Linux

An inode stores Linux file metadata, not its name or data. See how inode numbers and hard links work, then check inode usage with ls, stat, and df.

Docker Compose Cheatsheet

Docker Compose quick reference: lifecycle commands, Compose file directives, health checks, environment variables, profiles, scaling, and cleanup.

How to Configure Networking with Netplan on Ubuntu

Configure Ubuntu networking with Netplan using practical YAML examples for DHCP, static IP addresses, DNS, Wi-Fi, bridges, and safe remote changes.

smartctl Command in Linux: Check Disk Health with SMART

Use smartctl in Linux to check SMART health, read disk attributes, run self-tests, troubleshoot USB enclosures, and monitor NVMe wear.

Markdown Cheatsheet

Quick reference for Markdown syntax covering headings, formatting, links, images, lists, tables, code blocks, blockquotes, and common extensions.

ffmpeg Command in Linux: Convert, Compress, and Extract Media

Practical ffmpeg examples for converting between formats, compressing video with CRF, extracting audio, trimming clips, resizing video, and batch processing files on Linux.

What Is /dev/null in Linux

The Linux /dev/null device discards anything written to it and returns EOF when read. This guide shows how to silence stdout, stderr, cron output, and empty files.

Fix SSH "Host Key Verification Failed" Error

Resolve the SSH Host key verification failed error by removing the stale known_hosts entry with ssh-keygen -R after verifying the server is genuine.

Hard Links vs Symbolic Links in Linux

Understand the difference between hard links and symbolic links in Linux: how inodes work, when each type breaks, and which one to use for a given task.

How to Check if a Command Exists in Bash

Check whether a command exists in Bash with command -v, capture its path, validate several dependencies, and compare type, hash, and which.

setuid, setgid, and the Sticky Bit Explained

Understand the setuid, setgid, and sticky bit special permissions in Linux: what each one does on files and directories, how to set them, and the security risks.

GitHub CLI: Manage Repositories, Issues, and Pull Requests

Use GitHub CLI to create and clone repositories, manage pull requests and issues, inspect workflow runs, publish releases, and call the GitHub API.

curl vs wget: Differences and When to Use Each

Compare curl vs wget defaults, protocols, redirects, recursive downloads, API requests, and resume options to choose the right command for each task.

The most visible difference is the default output. wget saves the response to a file, while curl writes it to standard output.

https://linuxize.com/cheatsheet/pip/

SOCKMAP - TCP splicing of the future

Proper TCP socket splicing reduces the load on userspace processes and enables more efficient data forwarding. We realized that Linux Kernel's SOCKMAP infrastructure can be reused for this purpose.

as you may know, we run a global network of reverse proxy services.

SOCKMAP

How to Install and Use Ollama on Ubuntu: Run LLMs Locally

Install Ollama on Ubuntu, run large language models locally, manage downloaded models, use GPU acceleration, and send prompts through the local API.

Bash Subshells: Isolate Variables and Directory Changes

Bash subshells run commands in an isolated shell environment. This guide explains parentheses, variable scope, directory changes, command substitution, pipelines, and exit codes.

cut Cheatsheet

Quick reference for extracting fields, bytes, and characters with cut in Linux

hostnamectl Command in Linux: Set and Query Hostname

Use hostnamectl to view and change the Linux hostname. Covers static, transient, and pretty names, system metadata, remote hosts, and common errors.

Linux Pipes Explained: How to Use the | Operator

Linux pipes connect command output to another command's input. Learn the | operator, pipefail, stderr piping, xargs, named pipes, and process substitution.

Bash Array Operations: Length, Search, Slice, and Reverse

Practical Bash array operations for checking length, finding values, slicing, reversing, iterating, appending, prepending, and removing elements.

How to Use OpenSSL: Generate Keys, Certificates, and Test TLS

Practical OpenSSL guide for Linux: generate private keys, create CSRs and self-signed certificates, convert formats, inspect certificates, and test TLS connections.

How to Pass Arguments to a Bash Script

This guide explains how to pass arguments to Bash scripts, read positional parameters, loop over $@, set defaults, validate input, and parse flags with getopts.

reboot Cheatsheet

Quick reference for rebooting and scheduling restarts on Linux

ripgrep Cheatsheet

Quick reference for recursive text searches with the ripgrep command

Whois command in linux

The whois command looks up domain registration, registrar, name server, expiry, IP allocation, and AS number details from Linux.

Bash Arithmetic: Integer and Floating-Point Math

How to do arithmetic in Bash with the (( )) operator, $(( )) expansion, the let builtin, and bc or awk for floating-point math the shell cannot do natively.

How to Install Podman on Ubuntu: Rootless Container Alternative to Docker

Step-by-step instructions for installing Podman on Ubuntu, running rootless containers, building images with Buildah, and switching from Docker.

Bash String Manipulation: Substring, Replace, Length, and More

Bash string manipulation using parameter expansion: extract substrings, replace text, strip prefixes and suffixes, change case, and check for substrings with practical examples.

systemctl Command in Linux: Start, Stop, and Manage Services

Manage services on systemd-based Linux distributions with systemctl. This guide explains how to start, stop, restart, enable, and disable services, reload unit files, and inspect service status.

Bash Best Practices: Writing Safer, Cleaner Scripts

Practical Bash best practices for writing safer and more predictable scripts, covering strict mode, quoting, error handling, and everyday patterns.

So you've installed `fzf`. Now what? |

Software engineers are, if not unique, then darn near unique in the ease with which we can create tools to improve our own professional lives; this however can …

SFTP Cheatsheet

Quick reference for the Linux sftp client, covering login, navigation, transfers, and remote file management over SSH

fdisk Cheatsheet

Quick reference for fdisk commands: list disks, create partition tables, add partitions, change partition types, write changes, and quit safely