How to Access Help Online

UNIX Online Documentation

There are several ways to access online documentation:

TAMU Supercomputing Facility Website

Don't forget, documentation for many of the commercial applications running on our servers is also available on the TAMU Supercomputing website at: and
In addition to application documentation, the website provides up-to-date news and information regarding developments at the Facility which impact the user community.

How to use the "man" command

To access the online manual from the UNIX command line, use the man command. To read the manual for the C-shell (csh) enter:

k2% man csh

The output will look like this:

csh(1)                                                                  csh(1)


         csh - shell command interpreter with a C-like syntax

         csh [ -bcefinstvVxX ] [ argument ... ]


         csh, the C shell, is a command interpreter with a syntax reminiscent of
         the C language.  It provides a number of convenient features for
         interactive use that are not available with the standard (Bourne) shell,
         including filename completion, command aliasing, history substitution,
         job control, and a number of built-in commands.  As with the standard
         shell, the C shell provides variable, command and filename substitution.

This is only the first page of output and there is more to read.

You can use these keys in man:

Space show the next page
Enter scroll forward 1 line
d scroll forward 1/2 page
b go back to the previous page
/stuff find the string stuff in the document
n repeat the last find command
q quit
h help - shows keyboard commands

How to Find Things

To find something in the online manual use the whereis, whatis, and apropos commands.

whereis returns the location of a named file, for example:

k2%  whereis ls
ls: /usr/bin/ls /sbin/ls /usr/share/catman/u_man/cat1/ls.z

This means the "ls" program is in /usr/bin and also in /sbin/ls. Furthermore, the man page for ls is in /usr/share/catman/u_man/cat1/ls.z.

whatis returns a short description of a command or function. Example:

agave%  whatis gcc
gcc (1)                 - GNU project C and C++ compiler

means that help for gcc is in section 1 of the manual.

agave%  whatis strcat
strcat(3)       - Copies and appends strings inmemory.

means that help for strcat is in section 3 of the manual. You could use "man 3 strcat" to read this man page.

Sometimes you will get multiple responses:

agave%  whatis make
make (1L)            - GNU make utility to maintain groups of programs
make(1)               - Maintains, updates, andregenerates groups of programs.

this indicates that there are two make commands. To read about the GNU make, you could enter:

agave% man 1L make

Apropos keyword search

The apropos command will search for keywords in the descriptions of man pages. If you enter:

agave% apropos perl

you will get a list of all manual pages related to "perl". If there are a lot (as for perl) you can pipe the output through more:

agave% apropos perl | more


Sections of the Manual

The online manuals are divided into sections, numbered 1-8. The reference csh(1) means the csh command in section 1. The sections are:

1 User commands
2 System calls
3 Library routines, for use in programs
4 File formats (on the IBM, this section is for special files, device drivers, and hardware)
5 Miscellaneous (on the IBM this section is for configuration files)
6 Demos and games
7 Special files, device and network interfaces (on the IBM this section is for miscellaneous pages)
8 System administration commands
D Device Drivers (section D does not exist on the IBM)
l local commands; not used at TAMU SC
p public commands; not used at TAMU SC
n new commands; not used at TAMU SC
o old commands; not used at TAMU SC

On the SGIs some sections have an "intro" page giving more information on that section. If you wanted to learn what subroutines are available for C programming, you would enter:

man 3 intro
This intro page would inform you that section 3 is further classified into subsections for various types of subroutines: 3C for the standard C library, 3M for the math library, etc.

Location of the Online Manuals

The man command will only for help files in directories on your MANPATH. To see your MANPATH, type:


The locations of help files for the man command are:

/usr/local/man Manual for software in /usr/local/bin
/usr/dt/man Manual for the Common Desktop Environment (CDE)

You can add new directories to your MANPATH. For example, to add /usr/local/gnu/man, enter:

For C-shell (csh) users:

setenv MANPATH ${MANPATH}:/usr/local/gnu/man

For ksh and bash users:

export MANPATH

To make this MANPATH permanent, add it to your .cshrc file (csh users) or .profile (for ksh and bash).

User Environment

The man command uses the following environment variables:

Variable Use and Example
MANPATH List of directories to search for manual pages. To prepend new directories to the MANPATH use:
setenv  MANPATH  /usr/local/gnu/man:/usr/local/tex/man:$MANPATH
To append directories to the MANPATH use:
setenv  MANPATH  ${MANPATH}:/usr/local/gnu/man:/usr/local/tex/man

Note that when appending you must put ${MANPATH} in curly brackets.

PAGER Program to use to display the output. Default is "more -s". To use "less":
setenv  PAGER  "less -Cms"