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 /bin and /usr/bin directories. This will give you a one-line summary of the file’s function if available from man pages.

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 /etc :

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 ...