I create both shortcut menu items and buttons.
Under pull-down menu: TOOLS-Customize-CUI,
All I do is put the command, and answer prompts for distances, etc, then let the running command turn control over to me to select the 2 lines to chamfer or fillet. I also use this for a few standard "scales" I use frequently. For example: "c
hamfer d .25 .25;" then the command releases control to you to pick your 2 lines - Then I pick my 2 lines. If a polyline, it might look something like "
chamfer d .25 .25 p;" then the command releases control to you to pick the polyline. This is what you'd put in the command macro line of the CUI dialog. (possible examples only: YOUR personal research is REQUIRED for exact command and format.)
For first-timers, it LOOKS intimidating, but if you'll take just a moment and just examine the available tabs, etc, in the dialog box - it really is something you can figure out with only a little bit of patient effort. Its
NOT obvious, but it's also
NOT difficult. Also you might get a SPACE or a semicolon (

(which equals a space) wrong, and the command doesn't work quite like you expected, but that's ok. just go back and add or subract the " space " or " ; ", and you're good. A " space " and a semicolon "; " is the way you pot in the "Return" or "Enter" required by the command if you typed it in at the command prompt. Another thing - if you want the command to pause for you to pick something (or other input from you) use a back-slash ( \ ) at that point in your command.
You're creating a new command item, so you need to look into what the dialog box has you do, to insert a new command. It's right there, so open the Help while you examine the dialog box, and go for it !
Finally, PLEASE read up just a little from the CUI "Help". It'll talk about not modifying the base menu but making a sub-menu or something else to load so you don't corrupt the base default menu that came with your AutoCAD. A possible to approach might be to create a replaceacble menu from the entire base menu, and load that instead. Important possibility, if you're concerned about messing up the menu that came with your AutoCAD, but not necessarily the only right choice.
(Notice no mention of using "LISP.")
[ Hint: Among other things - like toolbar buttons, etc, I've modified my DEFAULT and my EDIT right-click shortcut menus ... EXTENSIVELY for my 3D Modeling - with NO LISP involved in a single command. Just sayin' ...!

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