ls command

ls stands for “list” and is used to display files and directories in Unix-like systems. It’s intentionally short — a design choice from early Unix to make commands fast and efficient to type.

A fundamental tool in Unix-like operating systems (Linux, macOS, BSD) used to list the contents of a directory. It displays the files and folders in your current working directory in alphabetical order

1. ls -l (Long Listing): Displays detailed information, including file permissions, owner, group, size in bytes, and last modification date.

2. ls -a (All): Includes hidden files (those starting with a dot, like .bashrc) which are normally hidden.

3. ls -h (Human-readable): Used with -l to show file sizes in a readable format like KB, MB, or GB instead of raw bytes.

4. ls -t (Time): Sorts files by the time they were last modified, showing the newest files first.

5. ls -r (Reverse): Reverses the sorting order (e.g., ls -tr shows oldest files last).

6. ls -R (Recursive): Lists all files in the current directory and all its subdirectories.

7. ls -F (Classify): Appends a character to indicate file type: / for directories, * for executables, and @ for symbolic links.

How ls Works Internally

When you run:

ls -l

Behind the scenes:

1. Opens the directory
2. Reads file names
3. Fetches metadata (if needed)
4. Sorts results
5. Prints output

Why ls is short

Unix commands are designed to be:

• Short (ls, cp, mv)
• Composable
• Efficient

This philosophy originated at Bell Labs and is standardized by POSIX

(Open .) command

open . is NOT a standard Linux command. It works on macOS, not typical Linux systems

On macOS

open .

• Opens the current directory (.) in Finder (GUI file manager)
• . means → current working directory

On Linux (Equivalent Commands)

xdg-open .

• Opens current directory in default file manager
• Works across most Linux distros (Ubuntu, Debian, etc.)

cd command (Change directory)

cd stands for change directory — it lets you navigate between folders in your system.

cd folder-name

Common Shortcuts

• cd .. → Go one level up
• cd ~ → Go to home directory
• cd / → Go to root directory
• cd - → Switch to previous directory

Pro tip :)

• Mastering cd is like mastering movement in a game — everything becomes faster, smoother, and more efficient.

touch command

touch is used to create empty files or update timestamps of existing files.

Basic Usage

touch file.txt

• Creates a new empty file (if it doesn’t exist)

Ways you can use touch

1. Create multiple files:

touch index.html style.css app.js

2. Update last modified time:

touch file.txt

3. Create files with paths:

touch src/components/Button.tsx

Conclusion

touch is the quickest way to turn ideas into files — zero friction, instant setup.

mkdir command

mkdir stands for make directory — it’s used to create new folders in your filesystem.

Basic Usage

mkdir folder-name

Common Use Cases

1. Create multiple folders:

mkdir src components utils

2. Create nested directories:

mkdir -p src/components/ui

3. Set permissions while creating:

mkdir -m 755 my-folder

Why this Matters

• Helps you quickly organize projects
• Essential for clean architecture & structure
• Widely used in scripts and automation

Pro tip :)

• A well-structured project starts with mkdir — clean folders, clean code.

Well, that's it for today guys. I hope you have learnt something valuable.

See you Tomorrow. Feel free to reach out to me in case if you need any help.