Basic Terminal Commands

Here you will learn the terminal commands engineers use every day. You do not need to memorize everything at once. Learn them little by little as you use them.

Command List

Command	Meaning	Main Use
pwd	Show current location	pwd
ls	List files and folders	ls, ls -la
cd	Change directories	cd Documents, cd .., cd ~
mkdir	Create a folder	mkdir my-project
touch	Create a file	touch index.html
rm	Delete files or folders	rm file.txt, rm -rf folder/
cp	Copy files or folders	cp a.txt b.txt
mv	Move or rename files or folders	mv old.txt new.txt
cat	Show file contents	cat README.md
open .	Open the current folder in Finder	open .
clear	Clear the screen	clear or Ctrl + L

Command Details

pwd - Check Where You Are

Short for Print Working Directory. It shows the path of the folder you are currently working in.

pwd

The output looks like this:

/Users/username

It is the first command to run when you get lost.

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ls - List Files and Folders

Short for List. It shows the contents of the current folder.

ls

Add the -la option to show hidden files and detailed information.

ls -la

total 48
drwxr-xr-x   8 username  staff   256 Mar 21 10:00 .
drwxr-xr-x  12 username  staff   384 Mar 20 09:00 ..
-rw-r--r--   1 username  staff  1234 Mar 21 10:00 README.md
drwxr-xr-x   5 username  staff   160 Mar 21 10:00 src

Files and folders that start with . are hidden files. They do not appear in normal ls output, but you can see them with -la.

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cd - Move Between Folders

Short for Change Directory. Use it to switch the folder you are working in.

# Move to your home folder
cd ~

# Move to the Documents folder
cd Documents

# Move up one folder
cd ..

# Move up two folders
cd ../..

# Move by specifying the full path
cd /Users/username/Documents/my-project

Tip: While typing a folder name after cd, press Tab to auto-complete it.

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mkdir - Create a Folder

Short for Make Directory. It creates a new folder.

mkdir my-project

Use the -p option to create missing parent folders at the same time.

mkdir -p my-project/src/components

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touch - Create a File

Creates an empty file.

touch index.html
touch README.md
touch .env

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rm - Delete Files or Folders

Short for Remove. It deletes files.

# Delete a file
rm old-file.txt

Use the -rf option to delete a folder and everything inside it.

rm -rf old-folder/

Warning: Files deleted with rm -rf do not go to the Trash. They are deleted immediately and permanently. Always check the target before running it. Never run rm -rf / or rm -rf ~/.

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cp - Copy Files or Folders

Short for Copy.

# Copy a file
cp README.md README.md.backup

# Copy a folder (`-r` is required)
cp -r src/ src-backup/

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mv - Move or Rename Files or Folders

Short for Move. It is used for both moving and renaming.

# Move a file to another folder
mv index.html src/index.html

# Rename a file
mv old-name.txt new-name.txt

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cat - Show File Contents

Short for Concatenate. It prints the contents of a file in the terminal.

cat README.md
cat package.json

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open . - Open in Finder on Mac

Opens the current folder in Finder, which is useful when switching between the terminal and the GUI.

open .

You can also open a specific file with its default app:

open index.html

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clear / Ctrl + L - Clear the Screen

Clears the terminal screen. It only hides old commands; it does not delete your work.

clear

You can also use Ctrl + L for the same effect.

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Time-Saving Tips

Tab Completion (Most Important)

If you type part of a command or file name and press Tab, the terminal auto-completes it.

cd Doc[Tab]
# -> completes to cd Documents/

If multiple candidates exist, press Tab again to see the list.

Use the Up and Down Arrow Keys to Access History

Pressing ↑ shows the last command you ran. It saves you from retyping commands you want to repeat.

↑  # one command back
↑  # two commands back
↓  # one command forward

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Practice: Create a Project Folder and Files

Follow these steps to create a project folder with commands.

# 1. Move to your home folder
cd ~

# 2. Check where you are
pwd
# -> /Users/username

# 3. Move to the Documents folder
cd Documents

# 4. Create a project folder
mkdir my-first-project

# 5. Move into the folder you created
cd my-first-project

# 6. Check the folder contents (it should be empty)
ls

# 7. Create files
touch index.html
touch README.md

# 8. Confirm the files were created
ls
# -> index.html  README.md

# 9. Write text into README.md
echo "# My First Project" > README.md

# 10. Check the contents
cat README.md
# -> # My First Project

# 11. Open it in Finder
open .

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Common Mistakes and Fixes

cd: no such file or directory

The folder does not exist or the name is misspelled.

# Bad: typo
cd Docuemnts

# Good: use Tab completion
cd Doc[Tab]

Permission denied

You do not have permission to access that file or folder. You may be trying to operate on a system file. In normal learning work, staying inside your home folder (~/) usually avoids this error.

The command seems stuck

Press Ctrl + C to stop the current command. Use it when the terminal appears frozen.

You worked in the wrong folder

Check your current location with pwd, then return to the home folder with cd ~ and move to the correct folder again.

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Next: Homebrew Installation