man

Man is short for "online manual." It's where you can find out information about Unix commands, Emacs, C++ and C libraries, and even man! The first useful thing to know about man is some of the command line arguments it takes:

  • -k - find me all things with this word or phrase in them.
    e.g. man -k c++ will give you all entries containing the word "c++".
  • -s - search only in this section (for instance, section 3C is the one where you can expect to find stuff about C and C++ libraries).
Try doing some searches. See if you can find:
  • The man page for the math library
  • The man page for g++
  • The man page for rcs
Sometimes, man pages give you pointers to other man pages with more information. The man page for rcs is an excellent example, since it points you to the man pages for co, ci and rlog, which are really more helpful.

If you don't know what command you are looking for, think of a word which is likely to be in the man file for that command (for instance, if you want a command to remove files) and do man -k that word. Sometimes you get a ton of answers; you can skip most of them. It helps if you can narrow the search down to a specific section.