The Most Common and Fundamental Command in the Linux World: ls

The most commonly used and fundamental command in the Linux world is <span>ls</span>.

What does ls do?

<span>ls</span> is used to view the files in the current directory.

Open the terminal and simply type:

ls

Press Enter, and you will see all the files and folders in the current directory!

app@linux-c:~$ ls
Desktop  Documents  Downloads  Music  Pictures  Public  snap  Templates  Videos

Let ls tell you more information

While the basic <span>ls</span> command is useful, sometimes we want to know more details: How large is this file? When was it created? What are its permissions? In this case, we need to use our “enhanced” version of ls:

ls -l

The <span>-l</span> option will display file information in a detailed list format. You will see results like this:

app@linux-c:~$ ls -l
total 36
drwxr-xr-x 2 app app 4096 Jun 20 10:49 Desktop
drwxr-xr-x 2 app app 4096 Jun 20 10:49 Documents
drwxr-xr-x 2 app app 4096 Nov 10 04:38 Downloads
drwxr-xr-x 2 app app 4096 Jun 20 10:49 Music
drwxr-xr-x 2 app app 4096 Jun 20 10:49 Pictures
drwxr-xr-x 2 app app 4096 Jun 20 10:49 Public
drwx------ 5 app app 4096 Nov 10 03:00 snap
drwxr-xr-x 2 app app 4096 Jun 20 10:49 Templates
drwxr-xr-x 2 app app 4096 Jun 20 10:49 Videos

Let me briefly explain the meaning of these mysterious codes:

• The first column (e.g., <span>-rwxr-xr-x</span>): File permissions (we will explain file permissions in detail in the next section)
• The fifth column (e.g., <span>4096</span>): File size (in bytes)
• The sixth to eighth columns: Last modification time
• The last column: File name

The leading letters are also interesting:

• <span>-</span> represents a regular file
• <span>d</span> represents a directory
• <span>l</span> represents a link file

Some Useful Tips

1. View Hidden Files:

   ls -a
   

   In Linux, files that start with a dot <span>.</span> are hidden files.

app@linux-c:~$ ls -al
total 136
drwxr-x--- 17 app app 4096 Nov 17 04:44 .
drwxr-xr-x  3 root    root    4096 Jun 20 10:48 ..
-rw-------  1 app app 2755 Nov 13 07:06 .bash_history
-rw-r--r--  1 app app  220 Mar 31  2024 .bash_logout
-rw-r--r--  1 app app 3794 Nov 10 04:42 .bashrc
drwx------ 15 app app 4096 Nov 10 04:48 .cache
drwx------ 15 app app 4096 Nov 10 04:39 .config
drwxr-xr-x  2 app app 4096 Jun 20 10:49 Desktop
drwxr-xr-x  2 app app 4096 Jun 20 10:49 Documents
drwxrwxr-x  3 app app 4096 Nov 10 04:48 .dotnet
drwxr-xr-x  2 app app 4096 Nov 10 04:38 Downloads
-rw-------  1 app app   20 Nov 10 09:12 .lesshst
drwx------  4 app app 4096 Jun 20 10:49 .local
drwxr-xr-x  2 app app 4096 Jun 20 10:49 Music
drwxr-xr-x  2 app app 4096 Jun 20 10:49 Pictures
-rw-r--r--  1 app app  872 Nov 10 10:33 .profile

1. Human-Readable File Sizes:

   ls -lh
   

   This will display file sizes in units like K, M, G.

app@linux-c:~$ ls -lh
total 40K
drwxr-xr-x 2 app app 4.0K Jun 20 10:49 Desktop
drwxr-xr-x 2 app app 4.0K Jun 20 10:49 Documents
drwxr-xr-x 2 app app 4.0K Nov 10 04:38 Downloads
drwxr-xr-x 2 app app 4.0K Jun 20 10:49 Music
drwxr-xr-x 2 app app 4.0K Jun 20 10:49 Pictures
drwxr-xr-x 2 app app 4.0K Jun 20 10:49 Public
drwx------ 5 app app 4.0K Nov 10 03:00 snap
drwxr-xr-x 2 app app 4.0K Jun 20 10:49 Templates
-rw-rw-r-- 1 app app   46 Nov 17 04:47 text.txt
drwxr-xr-x 2 app app 4.0K Jun 20 10:49 Videos

1. Sort by Time:

   ls -lt
   

   The most recent files will be listed first.