Intro to the CLI Flags

Learning objective: By the end of this lesson, students will be able to effectively use and combine flags with the ls command to modify its output.

As demonstrated in Navigating the File System we can use the ls command to see the files in a directory.

The default behavior of this command does not display hidden files (files that start with a ., like a .gitignore-global file). So, how do we view files like this? We can add what is called a flag to the ls command. Let’s do this now!

ls -a

Here, the letter a is a flag, indicated by the -. Flags are extra modifiers you can optionally add to commands. They change the behavior of the command.

The ls command has several other flags, such as -l. This flag lists the directories and files in a directory in a longer format with more details. Let’s test it!

ls -l

We can even combine these two flags and run both simultaneously:

ls -a -l

Or use a nifty shortcut by writing one dash - followed by the two options:

ls -al

We can write the flags in any order:

ls -la

Some applications also have long flags. These commands are spelled-out words and are preceded by two dashes --. A common long flag is --help, which some applications will have as a flag to display help information.