I checked some other common clis and it is show all right available options too. So I thought the argparse's help function is good enough too ;)

```
$ ps -etest
error: TTY could not be found

Usage:
 ps [options]

 Try 'ps --help <simple|list|output|threads|misc|all>'
  or 'ps --help <s|l|o|t|m|a>'
 for additional help text.

For more details see ps(1).
```

```
$ top test
top: unknown option 't'
Usage:
  top -hv | -bcHiOSs -d secs -n max -u|U user -p pid(s) -o field -w [cols]
```