types of man pages (man1, man2, man3, etc)

[Hektor]

I found where the man pages are located on my Linux machine. Once I get into the directory I expected just one directory but there are a whole bunch.

man1    man2    man3    man4    man5    man6    man7    man8    man9    mann    whatis

What are all of these directories? Which one does the "man" command use? Each directory has files in it and they will have the .x where x is the number as their extension. Here is an example in man4 dir:

arp.4           faith.4         icmp6.4         ip.4            ipsec.4         null.4          stderr.4        tcp.4           udp.4
bpf.4           fd.4            ifmib.4         ip6.4           lo.4            pty.4           stdin.4         termios.4       unix.4
divert.4        gif.4           inet.4          ipfirewall.4    netintro.4      random.4        stdout.4        tty.4           urandom.4
dummynet.4      icmp.4          inet6.4         ipl.4           networking.4    route.4         stf.4           tun.4

They appear to just be text files though and can be loaded in any text editor.

[Jordan]

Here are what the numbers mean:

1 - Commands available to users
2 - Unix and C system calls
3 - C library routines for C programs
4 - Special file names
5 - File formats and conventions for files used by Unix
6 - Games
7 - Word processing packages
8 - System administration commands and procedures

Basically, it is just a way to categorize the man pages.