Open terminal Ctrl + Alt + t and run this command:
whatis `compgen -c` | more
This will list all commands and a simple description of each command.
If you want to save the list you can redirect the result into an output file
whatis `compgen -c` > listOfCommands.txt
So why I used whatis command. The command man whatis gives:
Each manual page has a short description available within it.
whatis searches the manual page names and displays the manual page descrip‐ tions of any name matched.
so in easy words whatis give a general. description of each command
