This article was originally published on Medium on November 10, 2021.
Basics
When you first open a shell, you’re likely to be in your user’s home directory. All the files here belong to your user. What files you ask? Well, let’s find out. In your shell, type the following command and press the Enter or the Return button.
[bitmvr]:~ $ ls Applications Fonts Pictures Videos Desktop Library Documents Movies Downloads Music
Long List
The output from that command should show different directories and files. You may spot Desktop, Documents, Pictures, and more. What if you wanted to know when the file was created? Well, the ls command by itself does not present much information to the user. In order to get more information, we have to pass a flag to alter the output format. One of my favorite flags is -l . This will output the files in the long format.
[bitmvr]:~ $ ls -l total 64 drwx — — — @ 3 bitmvr wheel 96 May 29 2020 Applications drwx — — — @ 17 bitmvr wheel 544 Nov 9 15:13 Desktop drwx — — — + 17 bitmvr wheel 544 Oct 20 09:40 Documents drwx — — — @ 20 bitmvr wheel 640 Nov 9 13:37 Downloads drwxr-xr-x @ 4 bitmvr wheel 128 Apr 5 2019 Fonts drwx — — — @ 73 bitmvr wheel 2336 Aug 9 15:46 Library drwx — — — + 6 bitmvr wheel 192 Jul 6 16:16 Movies drwx — — — + 7 bitmvr wheel 224 Oct 23 2020 Music drwx — — — + 8 bitmvr wheel 256 Nov 12 2020 Pictures drwxr-xr-x @ 6 bitmvr wheel 192 Mar 29 2021 Videos
This format displays information in columns. Here is a high overview of what each column represents:
- The permissions of the file.
- The number of hard links that file contains.
- Which User owns the file.
- Which Group owns the file.
- The number of bytes for the file.
- The next three columns represent the last modified date of the file.
- The name of the file.
List All Files
In Linux and other Unix-like operating systems, hidden files begin with a dot. A few common files you will often see in your home directory are .bash_profile , .bashrc, and .bash_history.
In order to list these files, we need to add the -a flag (List all files) to our previous ls -l command.
[bitmvr]:~ $ ls -l -a total 64 -rw------- 1 bitmvr wheel 66158 Nov 9 20:18 .bash_history -rw-r--r--@ 1 bitmvr wheel 731 Jun 18 2020 .bash_profile drwx — — — @ 3 bitmvr wheel 96 May 29 2020 Applications drwx — — — @ 17 bitmvr wheel 544 Nov 9 15:13 Desktop drwx — — — + 17 bitmvr wheel 544 Oct 20 09:40 Documents drwx — — — @ 20 bitmvr wheel 640 Nov 9 13:37 Downloads drwxr-xr-x @ 4 bitmvr wheel 128 Apr 5 2019 Fonts drwx — — — @ 73 bitmvr wheel 2336 Aug 9 15:46 Library drwx — — — + 6 bitmvr wheel 192 Jul 6 16:16 Movies drwx — — — + 7 bitmvr wheel 224 Oct 23 2020 Music drwx — — — + 8 bitmvr wheel 256 Nov 12 2020 Pictures drwxr-xr-x @ 6 bitmvr wheel 192 Mar 29 2021 Videos
Tip: You can often times bundle command flags together. In the example above, instead of
ls -l -a, you can typels -la.
If done correctly, you will now be able to see any hidden files. With just two flags, we can now view a lot more information about the structure of our home directory. These are two of the most useful flags applied to the ls command. Hmm… what else could we do to make this output better?
Human Readable File Sizes
Given that we’re executing ls with the -l flag, we can append the -h flag as well. This will modify the output format so that we’re presented with human readable file sizes.
Note, I am going to also use the -a flag because I prefer to always view all files.
[bitmvr]:~ $ ls -lah total 584 drwxr-xr-x+ 80 bitmvr wheel 2.5K Nov 9 20:59 . -rw------- 1 bitmvr wheel 65K Nov 9 20:18 .bash_history -rw-r--r--@ 1 bitmvr wheel 731B Jun 18 2020 .bash_profile -rw-r--r--@ 1 bitmvr wheel 2.8K Nov 1 17:49 .bashrc rwx------@ 3 bitmvr wheel 96B May 29 2020 Applications drwx------@ 17 bitmvr wheel 544B Nov 9 15:13 Desktop drwx------+ 17 bitmvr wheel 544B Oct 20 09:40 Documents drwx------@ 20 bitmvr wheel 640B Nov 9 13:37 Downloads drwxr-xr-x@ 4 bitmvr wheel 128B Apr 5 2019 Fonts drwx------@ 73 bitmvr wheel 2.3K Aug 9 15:46 Library drwx------+ 6 bitmvr wheel 192B Jul 6 16:16 Movies drwx------+ 7 bitmvr wheel 224B Oct 23 2020 Music drwx------+ 8 bitmvr wheel 256B Nov 12 2020 Pictures drwxr-xr-x@ 7 bitmvr wheel 224B Oct 11 11:35 Projects drwxr-xr-x@ 6 bitmvr wheel 192B Mar 29 2021 Videos
Whew. That makes it a bit easier to know the size of any given file in the output. These few flags are usually all that one needs to be very effective reviewing files inside their shell. If you want to learn more, I highly recommend reading the man page for ls. In your shell, just type:
man ls
Happy reading and as always, keep hacking!