- Find Out About Commands with man
- Search for a Command Based on What It Does
- Quickly Find Out What a Command Does Based on Its Name
- Rebuild man's Database of Commands
- Read a Command's Specific Man Page
- Print Man Pages
- Learn About Commands with info
- Navigate Within info
- Locate the Paths for a Command's Executable, Source Files, and Man Pages
- Read Descriptions of Commands
- Find a Command Based on What It Does
- Find Out Which Version of a Command Will Run
The title of this chapter is "Learning About Commands," and that's what we've covered. By now, you've seen that there are a variety of ways to find out more about your options on the command line. The two big dogs are man and info, with their volumes of data and descriptions about virtually all the commands found on your Linux computer. Remember that whereis, whatis, apropos, and which all have their places as well, especially if your goal is to avoid having to wade through the sometimes overwhelming verbiage of man and info, an understandable but often impossible goal. Sometimes you just have to roll up your sleeves and start reading a man page. Think of it like broccoli: You might not enjoy it, but it's good for you.
It's true that many of the commands in this chapter overlap to a degree. For instance, man -k is the same as apropos and man -f is just like whatis, while whereis -b is functionally equivalent to which -a. The choice of which one to use in a given situation is up to you. It's still a good idea, however, to know the various similarities, so you'll be able to read shell scripts or instructions given by others and understand exactly what's happening. Linux is all about variety and choice, even in such seemingly small matters as commands run in the shell.