How to find hidden switches

tux_UAP · 08-24-2012, 10:59 AM

Is there a way to consistently find information on hidden switches for a command line program? For instance, I found an article which demonstrated using ps -aux | less. This works, but when I invoke ps --help I see no description of aux. It obviously does something because the output is substantially different when not using aux. How can I found what other switches might be lurking inside of a given command line program? Thanks.

UAP

austintx · 08-24-2012, 11:11 AM

commandlinefu.com has a very interesting list of command line tricks.
And here are more...
https://help.ubuntu.com/community/CommandLineResources

If you want to see all the switches for a given command, look it up here:
http://manpages.ubuntu.com/

tux_UAP · 08-24-2012, 12:48 PM

I realize now that the aux is not an individual switch, but a combination of a, u, and x. Thanks for the reply.

bcwagne · 08-24-2012, 04:36 PM

The --help switch usually only gives a few of the most common options. Going to the man pages, either on the internet or by typing 'man <command>' in the terminal will give you the whole story.

David the H. · 08-24-2012, 05:26 PM

Commands do sometimes have undocumented features. Generally this is caused by the developers not updating the documentation as fast as the program.

I imagine that these features are usually "discovered" by the developers mentioning them in discussions/newsgroups, by someone going to the trouble of digging through the source code, or occasionally simply by accident.