Update 21 September, 2018: This doesn't work at all for 10.13.6. If you're trying to activate on 10.13.6, find more details here: Activating Geometer’s Sketchpad in macOS 10.13.6 (and beyond?)
Update 26 July, 2017: Recently I found this not working any more. I had to send the command through Apple Remote Desktop (or run it locally on the machine). Even with the sleep commands (or without them), scripting seems to have died as an option for GSP. Maybe it will be resurrected later? The good news, I guess, is that now you can use double-quotes, too?
I had an old workaround for prepping GSP for Munki that didn't activate things in the sanctioned way.
The problem is the silent-install documentation as written is misleading. For example, this is the example given for a silent install for Mac OS X:
I had the command failing for me to register and to de-register. So I did some Googling and found some JAMFers running into the same problem: register/deregister Geometer's Sketchpad.
Turns out you need single quotes instead of double quotes. And you have to take out the dashes in the registration code.
There is an additional issue a user brings up of scripting the command not working but the command working fine if pasted directly into the terminal.
I've found a workaround for that (for Munki, and not Casper, but I'm assuming the issue is similar, and so the fix the same)—just putting some pauses in the scripts. I haven't experimented with what the exact thresholds are, but these seem to work.
/Applications/GSP5.app/Contents/MacOS/GSP5_Rel_KCPT_31_105 -license register -name 'Name of Your School' –code ************************
/Applications/GSP5.app/Contents/MacOS/GSP5_Rel_KCPT_31_105 -license deregister -name 'Name of Your School' –code ************************
When I took out the hyphens, switched double quotes to single quotes, and put in some pauses in the scripts, the scripts executed just fine.