Table of Contents
This section is covered in the system administration course, however we are attempting to ensure that you have the inner working details as well as the administration details.
Can you see when you read the man pages that the commands, file structures etcetera are divided into categories that are represented by numbers, for example - shutdown(8).
The following is a list of these categories:
1 Executable programs or shell commands 2 System calls (functions provided by the kernel) 3 Library calls (functions within program libraries) 4 Special files (usually found in /dev) 5 File formats and conventions e.g. /etc/passwd 6 Games 7 Miscellaneous (including macro packages and conventions), \ e.g. man(7), groff(7) 8 System administration commands (usually only for root) 9 Kernel routines [Non standard]
This was taken from the man page on "man"