#linux cheat sheet

From Zero to Super User — A Complete, Practical, and Progressive Cheat Sheet

This guide is written for anyone who wants to go from “I just installed Ubuntu/Zorin/Mint/Pop!_OS” to feeling like a complete Linux wizard. To put for my vintage gamers it is like learning (UP, Up, Down, Down, Left/Right, Left/Right on the NES).

Every single command is explained with:

What it literally does

Why you will actually use it in real life

Common options you’ll type 1000 times

Pro tips & gotchas

A difficulty tag: 🟢 Beginner | 🟡 Intermediate | 🔴 Advanced

Let’s begin.

PART 1 – 🟢 ABSOLUTE BEGINNERS (First 5 minutes in the terminal)

PART 2 – 🟢 FILE & FOLDER BASICS (You will use these every single day)

PART 3 – 🟡 INTERMEDIATE POWER TOOLS (You start feeling like a hacker)

PART 4 – 🔴 SYSTEM INFORMATION & MONITORING (When things go wrong)

PART 5 – 🔴 PACKAGE MANAGEMENT (Ubuntu/Debian family)

PART 6 – 🔴 PERMISSIONS & OWNERSHIP (The scariest and most important)

PART 7 – 🔴 ADVANCED ONE-LINERS YOU’LL SHOW OFF

PART 7 – 🔴 COMMANDS THAT MAKE YOU FEEL LIKE A GOD

(Use with care with great power comes great responsibility)

These are the one-liners and short sequences that make people watching over your shoulder whisper “holy crap…”

Copy-paste ready. Every single one has been battle-tested on real machines.

Bonus God-Tier One-Liner That Does Something Actually Useful

Instantly find and kill the process that’s hogging your CPU (one second execution)

ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%cpu | head -n 5 | tail -n 4 | awk '{print $1}' | xargs -I{} sudo kill -9 {}

(Top 4 CPU hogs die instantly. Use only when the machine is on fire.)

You now possess forbidden knowledge. Go forth and make sysadmins weep. 🐧⚡

Final Words

Bookmark this page. Within a month you’ll be typing these commands without thinking, and within a year you’ll be writing 10-line bash scripts that make Windows users cry.

Welcome to the terminal side. We have cookies (and infinite power). 🐧

Feel free to ask me for a printable PDF version, a categorized cheat-sheet wallpaper, or the next level (bash scripting, systemd, Docker, etc.). I’ve got you.

— CyberMaverick (Now a Terminal Wizard)

File Management Command Cheat Sheet

❇️ LINUX CHEAT SHEET

I recently moved my portfolio from my old UC Irvine server to my new one at www.jaytolentino.com, and so ran into copying my local files to a remote host. I've had to use these commands several times whenever I'm moving things around, so I thought it would be fitting to have it on my blog. Plus, I'll tag this and any similar future posts with Linux Cheat Sheet for any commands I want to remember.

Anyways, there are two commands one can use to move files over, and the one you choose depends on what you're copying.

Secure Copy command: scp usage: to copy one or multiple files securely over a network syntax:   scp [OPTIONS] /path/to/source user@host:/path/to/destination useful options:   -r, --recursive (recursively copies directories) scp Example: copying everything in my current directory to my remote host's public directory:   scp -r . [email protected]:~/public_html/

Rsync command: rsync usage: allows copying of only modified or new files syntax:   rsync [OPTIONS] /path/to/source user@host:/path/to/destination useful options:   -r, --recursive (recursively copies directories)   -u, --update (only copy new files or updated files)   --delete (deletes remote files that don't exist in source directory) rsync Example: copying everything in my current directory to my remote host's public directory:   rsync -ru --delete . [email protected]:~/public_html/

So the story goes that, after making my initial move from local to remote, I ended up changing some files. But if I kept using scp, then every file would be recopied to the remote host, even ones I didn't change. As the number of files grew, so did the time it took to transfer things over. After a quick search, I discovered rsync solved this problem for me.

Another problem I ran into with scp is that I couldn't "copy over" files that I deleted. I would then go into my remote host and manually delete them from there. But! rsync solves that problem when you include that handy --delete flag.

Securing rsync I'm sure you're wondering "Well, is rsync secure?" Answer: if you use it in conjunction with SSH, then yes. For more on SSH and rsync you can check out "Securing automated rysync over SSH"[1]. And if you want to combine this with cron jobs (which is a tool for automating jobs based on some schedule, e.g. copying files to a remote host at 5AM daily), you can check out "Using Rsync and SSH: Keys, Validating, and Automation" [3].

Alright, so here's the breakdown... Use scp when:

copying individual files

copying individual or multiple files once

you want no-fuss security

Use rsync when:

copying only modified or new files

deleting files on remote that were deleted locally

doing automated jobs, but as long as you secure it with SSH

Lastly, if you're really curious about how SCP works behind-the-scenes, take a look at "How the SCP protocol works" by Jan Pechanec. Thanks and hoped this helped you guys as much as it helped me!

Notes: There also exists the rcp command which functions similarly to scp. However, as you might realize from the name, scp secures files transferred over the network using encryption since it's based on the ssh protocol. See [2]