Getting additional information about commands

As we progress, you may see this book use many commands extensively and without exhaustive explanations. Without polluting this entire book with an introduction to Linux and useful commands, there are a couple of commands available that are really handy: man and info.

The man command, or manual command, is quite extensive and even has multiple sections when the same entry exists in different categories. For the purposes of investigating executable programs or shell commands, category 1 is sufficient. Let's look at the entry for the mount command:

$ man mount
... 
MOUNT(8) System Administration MOUNT(8)
NAME
 mount - mount a filesystem
SYNOPSIS
 mount [-l|-h|-V]
 mount -a [-fFnrsvw] [-t fstype] [-O optlist]
 mount [-fnrsvw] [-o options] device|dir
 mount [-fnrsvw] [-t fstype] [-o options] device dir
DESCRIPTION
 All files accessible in a Unix system are arranged in one big tree, the
 file hierarchy, rooted at /. These files can be spread out over sev‐
 eral devices. The mount command serves to attach the filesystem found
 on some device to the big file tree. Conversely, the umount(8) command
 will detach it again.
...
(Press 'q' to Quit)
$

 

Alternatively, there is the info command, which will give you information should info pages exist for the item you are looking for.

Note

Getting used to the style of the man and info pages can easily save you time by allowing you to access information quickly, especially if you don't have the internet.