[kolla]

Originally Posted by Sinphaltimus

Thanks kolla, I'm sure I'll need to know that at some point. Akira's answer pretty much nailed it.

Let me come with a small update - as I wrote the previous, I was puzzling over what trick I would use to check if a variable is not set - and now it just dawned upon me

lab ask
unset answer
echo noline "What is your name? "
set >NIL: answer ?
if "$answer" eq "*$answer"
  echo "Sorry, I demand an answer!"
  skip back ask
else
  echo "Hello $answer"
endif

See that trick? Unlike "sensible" shells of other operating systems, Amiga shell will treat unset variables as literal strings, including the dollar sign. So the solution is of course to check if "$var" is the same as "*$var", where the latter is the actual string with the dollar sign explicitly escaped (using *).

So now you can go ahead and call yourself _x or whatever you like