#!/usr/bin/perl -w
if (condition) {
   system '/usr/.../another.pl';
}
print "Location: http://test/ \n\n";

##</code><code>##

#!/usr/bin/perl -w
if (condition)
{
  `/usr/.../another.pl`
  # notice the use of the back quote.
}
print "Location: http://test/ \n\n";