Getting Help

1. man

man (short for “manual”) is a traditional form of online documentation in Unix
and Linux operating systems. Specially formatted files, “man pages”,
are written for most commands and distributed with the software.
Running man somecommand will display the man page for (naturally) the command or program somecommand.

Because
there are so many of them, man pages are grouped into enumerated
sections. This system has been around so long that you will often see
commands, programs, and even programming library functions referred to
with their man section number. For instance, you might see man(1). This tells you that man is documented in section 1 (user commands); you can specify that you want the section 1 man page for “man” with the command

#man 1 man

or

#man – S 1 man

Specifying the section that man should look in is useful in the case of multiple items with the same name.

Man Page Sections

Section Contents

Section 1	user commands (intro only)
Section 2	system calls
Section 3	C library calls
Section 4	devices (e.g., hd, sd)
Section 5	file formats and protocols (e.g., wtmp, /etc/passwd, nfs)
Section 6	games (intro only)
Section 7	conventions, macro packages, etc. (e.g., nroff, ascii)
Section 8	system administration (intro only)

so man page for

killpg (2)

is different from

killpg (3)

again to access ther different man pages we will go as

#man – S 2 killpg

#man – S 3 killpg

In addition to man(1), there are the commands whatis(1) and apropos(1), whose shared purpose is to make it easier to find information in the man system. whatis gives a very brief description of system commands, somewhat in the style of a pocket command reference. apropos is used to search for a man page containing a given keyword

to look for a man page of your choice run

apropos

like

this is what i get when i run

# apropos utmp
endutent [getutent] (3) – access utmp file entries
getutent (3) – access utmp file entries
getutid [getutent] (3) – access utmp file entries
getutline [getutent] (3) – access utmp file entries
pututline [getutent] (3) – access utmp file entries
setutent [getutent] (3) – access utmp file entries
utmp (5) – login records
utmpname [getutent] (3) – access utmp file entries
wtmp [utmp] (5) – login records
endutent [getutent] (3) – access utmp file entries
getutent (3) – access utmp file entries
getutid [getutent] (3) – access utmp file entries

so it will give all those listings that have “utmp” in its description or name

3. Online Forums
There are many online forums.
the best among them is Linuxquestions.org

All Linux queries can be posted at linuxquestions.org.

If you are not a member , register at linuxquestions.org.

References:
http://slackware.com