Is there a list of AutoCAD "sub-commands" and can the acad.pgp be formatted

I noticed that there are some commands that will only work after another command. For example, PER, or perpendicular, is an unknown command by itself. However, if I type L for line then PER is now an option. Is there a full listing or a tree diagram of these "sub-commands"? Can these commands be modified? I don't want to have to type TAN if I can type T or TT.

Thanks-

They are called command "modifiers". Another example would be M2P also typed as MTP. I don't believe these can be changed or modified.

The acad.pgp file can be modified (edited) in several ways. These "shortcuts" can be changed in many (not all cases) to suit your working habits or needs.

Consult your User's Guide > Command Modifiers for further information.

Another thing you may want to look at is 'Accelerator keys'

One thing I did notice with acad.pgp in AutoCAD2013 is that several of my custom commands no longer work. For example, I like to use LL for LAYUNISO and LLL and LAYISO. Now when I type LL, the command prompt says "LL must be called from within another command" (modifier perhaps). When I type LLL, the command prompt says "Reset Model space limits." Any idea how to change this?

If you are now using 2013, it would be a good idea to change that in your user profile.

ALIASEDIT is an express tool with which you can very easily change those shortcalls.

You will probably find all sorts of amazing information in the SYSVDLG (System Variable Settings dialog).

You can learn about and change how the commands and the system operates here.

If you work with 3D models, check out VIEWBASE for associative 2D representations.