Other sources of help

Getting help from programs themselves

Many programs can offer immediate help without the need for searching out man pages, info pages, or other documentation. It is a very widely-respected convention that programs offer help when invoked with an appropriate switch. Programs that support only what are called ``short options,'' options formed by a minus sign and a single letter, often print help when the -h switch is used. Programs that support ``long options,'' options formed with two minus signs and a word, often accept a --help switch. The long help option is particularly well-supported by GNU programs.

Example 11-3. Getting help from the gzip program

$ gzip --help
gzip 1.3.2
usage: gzip [-cdfhlLnNrtvV19] [-S suffix] [file ...]
 -c --stdout      write on standard output, keep original files unchanged
 -d --decompress  decompress
 -f --force       force overwrite of output file and compress links
 -h --help        give this help
 -l --list        list compressed file contents
 -L --license     display software license
 -n --no-name     do not save or restore the original name and time stamp
 -N --name        save or restore the original name and time stamp
 -q --quiet       suppress all warnings
 -r --recursive   operate recursively on directories
 -S .suf  --suffix .suf     use suffix .suf on compressed files
 -t --test        test compressed file integrity
 -v --verbose     verbose mode
 -V --version     display version number
 -1 --fast        compress faster
 -9 --best        compress better
 file...          files to (de)compress. If none given, use standard input.
Report bugs to <bug-gzip@gnu.org>.

Some programs also support a -? switch, which in most shells must be typed as -\?. Other programs will also print help whenever they are passed incorrect arguments.

Miscellaneous documentation

On many systems, miscellaneous documentation will be found under the /usr/doc or /usr/share/doc directory. For example, the mutt program, a popular email client has an extensive user manual that is neither man pages nor Texinfo documentation. On many systems, it can be found in /usr/share/doc/mutt/manual.txt.gz. In this case, the documentation is a compressed text file (as indicated by its extension). It can be viewed easily with zless, a version of less that automatically uncompresses compressed files.

Example 11-4. Viewing the mutt user manual.

  The Mutt E-Mail Client
  by Michael Elkins <me@cs.hmc.edu>
  version 1.3.28

  ``All mail clients suck.  This one just sucks less.'' -me, circa 1995

  Table of Contents

  1. Introduction
     1.1 Mutt Home Page
     1.2 Mailing Lists
     1.3 Software Distribution Sites
     1.4 IRC
     1.5 USENET
     1.6 Copyright

  2. Getting Started
     2.1 Moving Around in Menus
     2.2 Editing Input Fields
     2.3 Reading Mail - The Index and Pager
        2.3.1 The Message Index
  Status Flags
        2.3.2 The Pager
        2.3.3 Threaded Mode
        2.3.4 Miscellaneous Functions
     2.4 Sending Mail
        2.4.1 Editing the message header
        2.4.2 Using Mutt with PGP
        2.4.3 Sending anonymous messages via mixmaster.
     2.5 Forwarding and Bouncing Mail
     2.6 Postponing Mail
lines 1-32 

The power of Google

The Linux community developed in parallel with the Internet community. As a consequence, Linux information is often easily found on the Internet. Many times, help is as close as a search at google.com for your question and the word ``linux.'' Google also has a ``Linux topic search,'' available at www.google.com/linux.