The Linux Phrasebook
as suggested above by Telemachos is nice because it indexes commands by their functions
rather than the name of the command. If I don't know the name of the command to begin with (typical New Linux User) then I will have a hard time finding the command in a resource that is indexed by the name of the command. BUT if I want to perform an action on a file or file system I can look at that section in the Linux phrasebook and see all the commands related to the task I am trying to complete. Very nice layout for a Linux command reference.
A very useful command from the command line is apropos
. You can use this command to locate a command you are trying to find.
these will each return a list of commands related in some way to the search term you provided. Then you can use the man
pages to get detail on the commands returned