Linux process command help

Hi, for each command I need to explain what the command does and then show some of the output

For example:

ps << this command shows the running process

PID TTY TIME CMD

1250 pts/5 00:00:00 bash

1500 pts/5 00:00:00 ps.

The commands that I need solved are:

$ ps ax

$ ps ef

$ ps aux

$ ps ef f

(I'll be posting the other questions as seperate parts)