Command Line Cheat Sheet

January 09, 2021

Everyday and obscure (yet helpful) commands and references I use when working in the command line. While I have some of these memorized, there are others I need reminding, and others I that have serious enough consequences I’d rather copy and paste (e.g. Delete all folders, except [NAME]).

WARNING I encourage you to research the utilties and arguments in a command before blindly executing them in a terminal.

NOTE Commands tested in zsh 5.8 (x86_64-apple-darwin20.0) on macOS 11.1 (20C69)

Bash Prompt Symbols

  • ~ Current working directory is the current user’s home directory.
  • $ Current user is a standard user.
  • # Current user is the root user

Source: How To Change or Customize Bash Prompt In Linux {25 Options}


  • >> Append to file
  • > output to something other than stdout (overwrite file)
  • | feed output into another process
  • || OR operator
  • && AND operator

Current shell

Get a rough idea of what commands are available in remote shell instance.

$ echo $0

Source: How to Find Which Shell You Are Using on Linux

Check exit code from previous command

Check if the process exited successfully without using something like logging.

$ echo $?

Folder Size

Spot check the size of some output or see if the folder is a candidate for removal when cleaning up the file system.

$ du -sh [NAME]

Truncate file

Useful when debugging or want a clean slate.

: > filename

Pipe multi-line string (and remove all whitespace)

Remove the whitespace from a multi-line string and pipe to a specific utility. I use this with the Readability CLI quite a bit.

$ cat <<EOF | tr -d "[:space:]" | [UTILITY]
<!DOCTYPE html>
Hello, world!

Move files, including dot (hidden) files

Move all the files.

Enable glob support

$ shopt -s dotglob

Move files


Source: command line - How can I get mv (or the * wildcard) to move hidden files? - Ask Ubuntu

Delete all folders, except [NAME]

Clean up previous runs or logs except for the latest.

find . ! -name '[NAME]' -type d -exec rm -rf {} +

Make directory and move into it

Don’t repeat yourself

$ mkdir [DIRECTORY] && cd $_

Make intermediate directories

Make a new directory and any missing parent directories.


Go back to previous directory

$ cd -

File Stats

Get file stats, similar to File > Get Info in Finder.

$ stat [FILE]

Get file chmod numerical Value (macOS)

Get the file chmod numerical value to compare to the value you’re told to set it to.

$ stat -f “%OLp” [FILE]

List all processes

List all processes to see what’s running that shouldn’t be?

$ ps -A

Track process by port and kill said process

Port 8080 in use?! Find the process using the port and kill it.

# get process id
$ sudo lsof -i :[PORT]
# kill process
$ kill -9 [PID]

Follow changes in a file

Output new lines in a file to the terminal.

$ tail -f [FILE]

Copy set number of lines from the end of one file to another file

I only need a subset of the examples to run this test.

$ tail -n [NUM_LINES] [SRC_FILE] > [DEST_FILE]

Command history to shell script

The most recent commands worked and it’d be nice to have them saved to be ran again.

$ tail -n [NUM_LINES_PLUS_ONE] ~/.zsh_history | head -n [NUM_LINES] > [FILE].sh

Recursive grep

Search for text in directory and subdirectories.

$ grep -R ‘[SEARCH_TEXT]

List files and output information about symlinks. Useful when trying to find the location of a file.

$ ls -al

Output all file names

Output all file names (including those in subdirectories) and their relative path from the current working directory.

$ find .

Output contents of file to clipboard (macOS)

$ cat [FILE] | pbcopy

Paste to file (macOS)

$ pbpaste > [FILE]

Extract tgz to a specific folder

Extract tgz to a specific folder instead of the current working directory.

tar zxvf [FILE].tgz -C [DESTINATION]

Unzip with file wildcard

Unzip a collection of zip files in a folder.

$ unzip[FILE_PREFIX]*.zip’

Gunzip all files in a directory

$ for file in *.gz; do gunzip $file; done

Get a list of name servers

$ dig NS [domain]

Test name server

$ dig [domain] [@_NAME_SERVER]


Josh Aaseby
Software Engineer