When you have some spare time, something instructive to do that can help fill
gaps in your Unix knowledge and to get a better idea of the programs installed
on your system and what they can do is a simple
whatis call, run over
all the executable files in your
/usr/bin directories. This will
give you a one-line summary of the file’s function if available from
tom@conan:/bin$ whatis * bash (1) - GNU Bourne-Again SHell bunzip2 (1) - a block-sorting file compressor, v1.0.4 busybox (1) - The Swiss Army Knife of Embedded Linux bzcat (1) - decompresses files to stdout ... tom@conan:/usr/bin$ whatis * [ (1) - check file types and compare values 2to3 (1) - Python2 to Python3 converter 2to3-2.7 (1) - Python2 to Python3 converter 411toppm (1) - convert Sony Mavica .411 image to ppm ...
It also works on many of the files in other directories, such as
tom@conan:/etc$ whatis * acpi (1) - Shows battery status and other ACPI information adduser.conf (5) - configuration file for adduser(8) and addgroup(8) adjtime (3) - correct the time to synchronize the system clock aliases (5) - Postfix local alias database format ...
Because packages often install more than one binary and you’re only in the
habit of using one or two of them, this process can tell you about programs on
your system that you may have missed, particularly standard tools that solve
common problems. As an example, I first learned about
watch this way,
having used a clunky solution with
for loops with
sleep calls to do the
same thing many times before.