System() Methods in CGI Scripts Not Working

There’s probably a very simple explanation for this, but here 'goes:

I have a few CGI scripts. A couple of them make system() calls to launch
shell scripts. These scripts work fine on the command line, but when I
launch the exact same script by visiting it in my browser, the page
loads indefinitely.

I think this indicates a permissions problem. Is there anything I can do
to circumvent this? The server I’m running on is one I don’t control.

Okay, after much searching, I’ve discovered that the string I’m passing
to system() is tainted because it comes from POST data. I suppose
entering “rm *” in to any field WOULD be bad news. Lesson learned!