Ls Command in Linux (List Files and Directories)

What is ls?

The ls command stands for “list”. It is used in Linux/Unix to display the contents of a directory.

Basic Syntax

ls [options] [path]

• options: Optional flags to modify the output

• path: The directory to list (default is the current directory)

Step-by-Step Usage

 Step 1: List Files in Current Directory

ls

This shows files and directories in the current directory (excluding hidden ones).

Step 2: Show Hidden Files

Hidden files start with a dot (.), like .env or .git.

ls -a

Output includes files like .bashrc, .gitignore.

Step 3: Long Listing Format (Detailed Info)

ls -l

Shows:

• File type and permissions

• Number of links

• Owner

• Group

• Size

• Date/time

• Filename

 Example:

-rw-r--r--  1 user group   1234 Apr  5 12:34 file.txt

Step 4: Combine Options (e.g., Long + Hidden)

ls -la

Shows all files with detailed info.

Step 5: Human-Readable Sizes

ls -lh

File sizes are shown in KB/MB/GB instead of bytes.

Step 6: Sort by Time (Newest First)

ls -lt

Lists files sorted by modification time (latest first).

Step 7: Reverse Order

ls -lr

Lists in reverse alphabetical or time order (if combined with -t).

Step 8: List Files in a Specific Directory

ls /etc

List contents of the /etc directory.

Step 9: Recursively List All Files and Sub-directories

ls -R

 Shows the entire directory tree starting from the current directory.

Step 10: Colored Output

Most modern distros support ls --color or just color by default.

ls --color

 Colors differentiate file types (directories, links, executables).

Common ls Options Summary

Option	Description
-a	Include hidden files
-l	Long listing format
-h	Human-readable sizes (use with -l)
-R	Recursive list
-t	Sort by time (newest first)
-r	Reverse sort order
-S	Sort by file size
-d	List directories themselves, not contents

Examples

1. List files in /var/log sorted by size:

ls -lhS /var/log

2. Show hidden files with details in home:

ls -la ~

3. List only directories:

ls -d */

Pro Tips

• Combine options freely like ls -lhtr

• Use alias ll='ls -lh' for quicker long-listing

Practice Challenge

Try running:

ls -lahR /etc

To explore how /etc is structured recursively with all files and directories, including hidden ones.