Linux Commands Cheat Sheet

Files and folders

rm has no recycle bin. What it deletes is gone.

• List Everything in this folder, hidden files included, with sizes and permissions.Copy ls -lah
• Where am I The full path of the current folder.Copy pwd
• Make folders Create a folder, and any missing parent folders with it.Fill in mkdir -p {{path}}
• Copy Copy a file, or a folder with everything in it.Fill in cp -r {{source}} {{target}}
• Move or rename Move something, or give it a new name.Fill in mv {{source}} {{target}}
• Delete Delete a file or a whole folder, without asking.Fill in rm -rf {{path}}

Read files

• Print a file Show the whole file in the terminal.Fill in cat {{file}}
• Page through Scroll through a long file. Press / to search and q to quit.Fill in less {{file}}
• First lines The first 20 lines.Fill in head -n 20 {{file}}
• Follow a log Show new lines as they are written. Ctrl+C stops it.Fill in tail -f {{file}}
• Count lines How many lines the file has.Fill in wc -l {{file}}
• Compare The lines that differ between two files.Fill in diff {{file1}} {{file2}}

Find things

• Search in files Every line containing the text, in this folder and below, with line numbers.Fill in grep -rn "{{text}}" .
• Find by name Files whose name matches, for example *.log.Fill in find . -name "{{pattern}}"
• Which program The file that runs when you type a command.Fill in which {{command}}
• Search history Commands you ran before that contain the text.Fill in history | grep {{text}}
• Big folders The size of everything here, biggest last.Copy du -sh * | sort -h
• Free disk space Used and free space on every disk.Copy df -h

Permissions

In 644, the digits are owner, group and everyone else. 6 is read and write, 4 is read only, 7 adds execute.

• Make executable Let a script be run as a program.Fill in chmod +x {{file}}
• Set permissions The owner can read and write, everyone else can only read.Fill in chmod 644 {{file}}
• Change owner Give a file or a whole folder to another user.Fill in sudo chown -R {{user}} {{path}}
• Run as root Run one command with administrator rights.Fill in sudo {{command}}
• Again, with sudo Repeat the previous command as root, after a "permission denied".Copy sudo !!
• Who am I The user you are logged in as.Copy whoami

Processes

• Find a process Running processes matching a name, with their process IDs.Fill in ps aux | grep {{name}}
• Live monitor CPU and memory use, updating live. q quits. htop is nicer if installed.Copy top
• Stop a process Ask a process to stop. kill -9 forces it.Fill in kill {{pid}}
• Stop by name Stop every process with that name.Fill in pkill {{name}}
• Who uses a port The program listening on a port.Fill in sudo ss -ltnp | grep :{{port}}
• Memory Used and free memory.Copy free -h

Network and archives

• Download Download a file, following redirects, and keep its name.Fill in curl -LO {{url}}
• Check a URL Only the response headers: status code, redirects, content type.Fill in curl -I {{url}}
• Connect Open a shell on another machine.Fill in ssh {{user}}@{{host}}
• Copy over SSH Copy a file to another machine.Fill in scp {{file}} {{user}}@{{host}}:{{path}}
• Pack Compress a folder into one .tar.gz file.Fill in tar -czf {{name}}.tar.gz {{folder}}
• Unpack Extract a .tar.gz file here.Fill in tar -xzf {{file}}