I've had the same problem. For example if you do a len($var) and $var wasn't defined on the command line, you get a script error. I get around this with an IF check on the command line variable first, like this...

code:

---

if $var
 SELECT
 CASE $var="one"
  $num=1
 CASE $var="two"
  $num=2
 CASE $var="three"
  $num=3
 CASE 1
  $num=0
 ENDSELECT
else
 $num = 0
endif
? $num

---

This doesn't answer your question, but I hope it helps. Maybe KIX needs a DEF($var) type function so one can check if the variable was assigned on the command line.

Shawn.