http://www.fmi.uni-passau.de/archive/doc/unix/unixhelp/Unixhelp/manual_.html (Einblicke ins Internet, 10/1995)The command man gives you access to an on-line manual containing a complete description of every command available on this system.
man can also provide you with one line descriptions of commands specified by name; or for all commands whose description contains any of a set of keywords.