Linux Commands Cheat Sheet: 60 Commands by Task

New to this?Ping explains the hardest part in plain words.

Open all explanations

Bookmark this one. It's a Linux commands cheat sheet sorted by the job in front of you, not by the alphabet: find the task, grab the command, and get on with your day. Nearly all of it works on any Linux system; the apt package commands are the Ubuntu and Debian way of installing software.

#Getting around (and getting help)

• pwdShows the full path of the folder you're in right now.
• lsLists what's in the current folder.
• ls -laLists everything, hidden files included, with permissions, owner, size and date.
• cd folderMoves you into a folder. cd on its own takes you home.
• cd ..Moves you up one folder.
• cd -Jumps back to the folder you were in before.
• man commandOpens the manual for a command. Press q to quit, / to search.

$ pwd
/home/alex
$ mkdir -p projects/site
$ cd projects/site
$ pwd
/home/alex/projects/site
$ cd -
/home/alex

#Files and folders

• mkdir -p a/b/cMakes a folder, plus any missing folders above it, with no error if it already exists.
• touch file.txtCreates an empty file, or updates the timestamp on one that exists.
• cp file.txt copy.txtCopies a file.
• cp -r folder backupCopies a folder and everything inside it.
• mv old.txt new.txtRenames a file, or moves it if you give a folder as the second name.
• rm file.txtDeletes a file.
• rm -r folderDeletes a folder and everything in it. Add -i to be asked before each file.

$ mkdir -p ~/notes
$ cd ~/notes
$ touch todo.txt
$ cp todo.txt todo.bak
$ mv todo.bak old.txt
$ ls
old.txt  todo.txt
$ rm old.txt
$ ls
todo.txt

#Reading files

• cat file.txtPrints a whole file. Best for short ones.
• less file.txtOpens a long file one screen at a time. Arrow keys scroll, q quits.
• head -n 20 file.txtShows the first 20 lines. Leave out -n and you get 10.
• tail -n 20 file.txtShows the last 20 lines, where the newest entries in a log usually are.
• tail -f app.logKeeps the file open and prints new lines as they're added, so you can watch a log live. Ctrl+C stops it.
• wc -l file.txtCounts the lines in a file.

#Searching

• grep "error" app.logPrints every line in the file that contains the word. Add -n for line numbers.
• grep -ri "error" /var/logSearches every file in a folder and the folders inside it, ignoring upper and lower case.
• find . -name "*.log"Finds files by name, starting from the current folder. * matches anything.
• which python3Shows where a command's program lives. No output means it isn't installed, or isn't anywhere your shell looks for commands.
• historyLists the commands you've run. Pipe it into grep to find one: history | grep ssh.

$ head -n 2 app.log
start ok
error: disk full
$ grep -n error app.log
2:error: disk full
4:error: timeout
$ wc -l app.log
4 app.log

#Permissions and users

• chmod +x script.shMakes a file executable, so you can run it with ./script.sh.
• chmod 644 file.txtSets permissions by number: here the owner can read and write, and everyone else can only read.
• sudo chown alex:alex file.txtChanges who owns a file (user, then group).
• sudo commandRuns a single command as the administrator (root).
• whoamiPrints the user you're logged in as.
• idShows your user ID and every group you belong to.
• sudo useradd -m samCreates a new user with a home folder.
• sudo passwd samSets or changes a user's password.
• sudo usermod -aG docker samAdds a user to a group. The -a matters: without it, -G replaces all of their other groups. The change applies the next time they log in.

$ ls -l deploy.sh
-rw-rw-r-- 1 alex alex 26 Nov  7 23:15 deploy.sh
$ chmod +x deploy.sh
$ ls -l deploy.sh
-rwxrwxr-x 1 alex alex 26 Nov  7 23:15 deploy.sh
$ ./deploy.sh
deployed

ELI5: explain it simply▾

Ping explainsNo experience needed.

THE WORDS

Permissions

Rules for who can read a file, change it, or run it as a program.

rwx

Read, write and execute. A dash means that permission is off.

Executable

A file Linux is allowed to run as a program.

THE IDEA

Think of -rw-rw-r-- as three sets of keys: one for the owner, one for their group, and one for everyone else. Before chmod +x, nobody holds the "run it" key. After it, every set has an x in it, so the script can run.

#Processes

• ps auxLists every running process, with its owner, process ID (PID), CPU and memory use.
• topA live, updating view of what's using the most CPU and memory. q quits.
• kill 1234Asks the process with that PID to stop. kill -9 1234 forces it if it won't.
• pkill nameStops processes by name instead of by PID. It matches part of a name too, so check what it will hit with pgrep -l name first.

$ sleep 300 &
[1] 369
# the [s] stops grep from listing itself
$ ps aux | grep [s]leep
alex       369  0.0  0.0   3136  2008 pts/0    S    23:19   0:00 sleep 300
$ pgrep -l sleep
369 sleep
$ pkill sleep
[1]+  Terminated              sleep 300
$ ps aux | grep [s]leep
# no output: the process is gone

#System and disk

• df -hShows how full each disk is, in sizes like G and M.
• du -sh folderShows the total size of one folder.
• free -hShows how much memory is used and available.
• uname -aPrints the kernel version and other system details.
• uptimeShows how long the system has been running and how busy it's been.

#Networking

• ip aShows your network interfaces and their IP addresses.
• ping -c 4 example.comSends 4 test packets to check whether a host answers and how fast.
• curl https://example.comFetches a web page or API response and prints it. Add -I to see only the headers.
• ss -tulpnLists the TCP and UDP ports listening for connections, with the program using each (run with sudo to see them all).
• ssh alex@serverOpens a terminal on another machine over an encrypted connection.
• scp file.txt alex@server:~/Copies a file to another machine over SSH.

#Services and logs

• systemctl status nginxShows whether a service is running, plus its latest log lines.
• sudo systemctl restart nginxStops and starts a service, usually after you change its config.
• sudo systemctl enable --now nginxMakes a service start at boot, and --now starts it right away too.
• journalctl -u nginxShows the logs for one service. Add --since today to cut it down.
• journalctl -fFollows the system log live, like tail -f for everything.

#Packages and archives

• sudo apt updateRefreshes the list of available packages. It doesn't install anything by itself.
• sudo apt upgradeUpgrades the packages you already have to their newest available versions.
• sudo apt install nginxInstalls a package. On Fedora and Red Hat systems, the same job is sudo dnf install.
• tar -czf backup.tar.gz folderPacks a folder into one compressed file: c for create, z for gzip, f for the file name.
• tar -xzf backup.tar.gzUnpacks it again into the current folder (x for extract). Use -tzf to list what's inside first.
• unzip file.zipUnpacks a .zip file into the current folder. If it's not installed, sudo apt install unzip adds it.

$ tar -czf site-backup.tar.gz projects/site
$ tar -tzf site-backup.tar.gz
projects/site/
projects/site/index.html
projects/site/deploy.sh
projects/site/app.log
$ ls -lh site-backup.tar.gz
-rw-rw-r-- 1 alex alex 262 Nov  7 23:15 site-backup.tar.gz

#Going past the Linux commands cheat sheet

A cheat sheet tells you what to type. It doesn't build the habit of knowing which command to reach for, and that only comes from using them on something. A spare PC or a virtual machine running Ubuntu is plenty, and our homelab projects for your resume give you a reason to use all of this.

Run these commands step by step

Linux Fundamentals, Level 1 of every ProCourse, is where you actually do this, with labs and quizzes in a simulated terminal in your browser. Level 1 is free.

Open ›

opnF.sh

Hands-on guides from the team that builds the labs you practice in.