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Linux whatis command summary with examples

whatis allows you to display one-line manual page descriptions.
  1. Purpose - Learn what whatis is for and how to find help.
  2. Options - Review a few common options and arguments.
  3. Examples - Walk through code examples with whatis.
  4. A tip - Finish off with one more insight.
Paul Alan Davis, CFA, October 3, 2016
Updated: July 25, 2018
In this tutorial, 2 of 100, below find a 3-4 minute introductory video, a text-based tutorial and all of the code examples from the video.

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The Linux whatis command

Beginner

Learn to find quick summaries of commands at the Linux command line.

Video Tutorial

Linux whatis command summary with examples (3:35)

Videos can also be accessed from the YouTube Playlist.

Video Script

The Command and Why You Need It

Our second word, or command to memorize is whatis from the category Help.

whatis allows you to display one-line manual page descriptions. We will cover user manual pages, but just so you know whatis pulls the shortest description from those pages.

If it helps, think of commands as mini programs and most have this structure. First, type the command, second the -option(s) and third the argument(s).

The whatis command has 13 options and the argument is typically another command. It is lowercase whatis followed by one or several optional options, then the command name and Enter.

Here we will cover two of the more important options. The first is whatis -h, or the long version, whatis --help, for a short help screen.

Second is whatis --usage which shows you syntax. Again, the argument here is another command.

So why is whatis an important command? Well, it's the quickest way to find your bearings and remember what a command does. And now you know how to do that.

Demonstration

Okay, the best way to embed this in your memory is by typing in your own terminal window.

Find this on your Mac using a program called Terminal. On Linux use Terminal or Konsole, and currently Microsoft is adding this functionality to Windows 10.

Here we go, type whatis -h with no arguments, Enter and look, the 13 options I mentioned, with the short and long versions.

$ whatis -h Usage: whatis [OPTION...] KEYWORD... -d, --debug emit debugging messages -v, --verbose print verbose warnings messages -r, --regex interpret each keyword as a regex -w, --wildcard the keyword(s) contain wildcards -l, --long do not trim output to terminal width -C, --config-file=FILE use this user configuration file -L, --locale=LOCALE define the locale for this search -m, --systems=SYSTEM use manual pages from other systems -M, --manpath=PATH set search path for manual pages to PATH -s, --sections=LIST, --section=LIST search only these sections (colon-separated) -?, --help give this help list --usage give a short usage message -V, --version print program version Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options.

Next, to see the syntax, type whatis--usage.

$ whatis --usage [--debug] [--verbose] [--regex] [--wildcard] [--long] [--config-file=FILE] [--locale=LOCALE] [--systems=SYSTEM] [--manpath=PATH] [--sections=LIST] [--section=LIST] [--help] [--usage] [--version] KEYWORD...

And last, let's go without options, include an argument whatis and look, it pulls the short description of whatis, just as we wanted.

$ whatis whatis whatis (1) - display one-line manual page descriptions

A Final Tip

Okay now you know how to use whatis. And you know the syntax for commands, options and arguments.

One last tip about the whatis command. Just like most in the help category, you don't have to worry about messing things up, they're all pretty safe.

Okay, thanks for visiting today. I hope this was a fun exploration of the whatis command.


Learn More About The Series

For an overview of all 100 videos, the 8 quizzes, a cheat sheet, the categories and a Q&A section, visit:


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