Chapter 1. The Philosophy of System Administration

11

Note

Red Hat Linux uses the man command to display online help text. The text to be displayed is known

as a man page, and is displayed using the following command:

man

man page

(Replace

man page

with the name of the desired man page.)

Often you will see a man page followed by a number or letter within parentheses; this number or letter

denotes the section under which the man page is filed. The sections include:

  Section 1   User commands

  Section 2   System calls

  Section 3   Subroutines

  Section 4   Devices

  Section 5   File formats

  Section 6   Games

  Section 7   Miscellaneous

  Section 8   System administration

  Section l   Local

  Section n   New

It should be noted that many of the man pages have gotten their section classifications in years past,

sometimes making the sections more of a historical curiosity than a factual classification system.

However, there is one instance when the section number is important: when more than one man

page exists with the same name. One example is chroot(1) and chroot(2). The first man page

documents the chroot user command, while the second documents the chroot system call. If you

enter the command man chroot, you will see the man page for the chroot user command

3

. In order

to view the man page for the chroot system call, you must include the section number:

man 2 chroot

Once you are displaying a man page, you are actually using a text display program known as a pager .

To display subsequent screens, press the [Space] key; to quit, press [Q]. The [H] key will display help

for the pager.

  crontab(1)

and

crontab(5)

man pages   Command and file format documentation for using

cron

.

  at(1)

man page   Schedule commands and scripts for execution at a later time with this utility.

  bash(1)

man page   Learn more about the default shell (and shell script writing) with this docu 

mentation.

  perl(1)

man page   View pointers to the many man pages that make up perl's online documen 

tation.

3. There is a set order which man uses to search the sections; by default it is configured to look first for

user commands, then system administration related information, and then at the rest of the sections in

normal order.