The Whatis Command

THE WHATIS COMMAND

Whatis is a funny command that might come in handy as you learn Linux. Let´s give an example, we want to know what the command ¨cp¨ does:
NOTE: On some systems you have to build the database first by running "/usr/sbin/makewhatis" as root ( Thanks Owyn )

CODE

$ whatis cp
cp (1) - copy files and directories

Or the command ifconfig:

CODE

$ whatis ifconfig
ifconfig (8) - configure a network interface

Now we can do a lot more with whatis, imagine you want to have the information on all the commands stored in, let´s say, /usr/bin. We will have to move to that directory first:

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$ cd /usr/bin

And then we give the next command:

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$ ls | xargs whatis | less

( the ¨|¨ are pipe signs, the ¨shfit \¨ key )

This is a part of the list you will get ( scoll page with the spacebar, and close with Q ):

QUOTE (Text @ Screen)

411toppm (1) - convert Sony Mavica .411 image to PPM
a2p (1) - Awk to Perl translator
aclocal: nothing appropriate
aclocal-1.4: nothing appropriate
aconnect (1) - ALSA sequencer connection manager
acroread: nothing appropriate
activation-client: nothing appropriate
adddebug: nothing appropriate
addftinfo (1) - add information to troff font files for use with groff
addr2line (1) - convert addresses into file names and line numbers
addxface: nothing appropriate
alsamixer (1) - soundcard mixer for ALSA soundcard driver, with ncurses interface
amixer (1) - command-line mixer for ALSA soundcard driver
amor: nothing appropriate
animate (1) - animate a sequence of images
anytopnm (1) - convert an arbitrary type of image file to PBM, PGM, or PPM

( For the very curious ones: ls = list directory contents, xargs = build and execute command lines from standard input, less = opposite of more )

You can do this in any directory you like.

HINT: /bin, /usr/bin/, /sbin, /usr/sbin, and /usr/X11R6/bin are the most interesting directories to look for commands and their ¨whatis¨ explanation.

Have fun exploring !

Bruno

-- Aug 19 2003 ( Revised Dec 10 2005 ) --