If you want to identify the content of a particular directory in Linux, you can use the ls command. This command is essential for navigating and managing your files in Linux, and here is the step-by-step guide on how to use it:

The ls command basic syntax

By default, the ls command lists the contents of the current directory. Just type the following on your Linux terminal:

ls

This command provides a simple list of the files and directories in the current directory

Desktop  Documents  Downloads  Music  Pictures  Videos

Listing Files with Details

Using the ls command with the -l option , it allows you to list files and directories with detailed information like permissions, ownership, size, and modification date:

ls -l

Running the above command will give you an output with the following listing format:

drwxr-xr-x  2 user group 4096 Aug 31 10:20 Desktop
-rw-r--r--  1 user group  543 Aug 30 08:15 file.txt

We can interpret the output as follows:

• The first column contains file permissions: drwxr-xr-x and -rw-r–r–
• The second column contains the number of links (hard links).
• The third column containers the owners of the files called user in this case
• The fourth column contains the group to which the owner of the file belongs to.
• The fifth column contains files sizes in bytes.
• The sixth column contains the date and time of last modifications to the files.
• The seventh column contains the filenames and directories associated to the previous columns.

RECOMMENDED READING: How to use the cd command to navigate Linux directories

Including Hidden Files

Files that begin with a dot (.) are hidden by default. To list all files, including hidden ones, use the -a option.

ls -a

When you use ls with the -a option, it will list all files in the current directory including the hidden files that start with dots in their names.

Combining Options for Detailed Hidden Files

To make a detail list of files including hidden files, you can use ls with the -la options combination:

ls -la

Sorting the List

The ls command also allows you to sort the output based on various criteria. For example, to sort files by modification time, you can use the -t option:

ls -lt

The -lt options combination will produce a list of files and directories starting with the latest modification date and time:

-rw-r--r--  1 user group  543 Aug 31 10:20 latest-file.txt
-rw-r--r--  1 user group  321 Aug 30 08:15 older-file.txt

For reverse order, add the -r option:

ls -ltr

Listing Files in Human-Readable Format

By default, the ls command produces files sizes in bytes. But you can use the -h option along with -l to display sizes in KB, MB, etc.

ls -lh

The -lh options combination will display file sizes in kilobytes:

drwxr-xr-x  2 user group 4.0K Aug 31 10:20 Desktop
-rw-r--r--  1 user group 543K Aug 30 08:15 file.txt

Recursive Listing

To list all files and directories, including the contents of all subdirectories, use the -R option.

ls -R

This command will produce the following sample output:

.:
Desktop  Documents  Downloads

./Desktop:

./Documents:
file1.txt  file2.txt

Listing Directory Information

If you want to see only the directories, not files, you can use the following combination:

ls -d */

Listing Files by Size

You can list files by sorting them from the largest files to the smallest size using the -S option:

ls -lS

Here is the sample output of using the -lS options combination:

-rw-r--r--  1 user group 1.2M Aug 31 10:20 largefile.txt
-rw-r--r--  1 user group  543 Aug 30 08:15 smallfile.txt