[note: for some reason, your perl script came through
(at least on my email client) as an attachment. if you
can stop that happening, that would be nice.]
-------------
> for ($i=0; $b[$i] != undef; $i++)
!= is a numeric comparison.
Line 1544 of list is:
#stopped at 867
and in perl's book, that isn't a number.
> for ( $i = 0; !!$b[$i] ; $i++)
! alone, is a generic 'not'. It is neither a numeric nor
a string operator.
!! is redundant. It means 'not not'. You can just leave it out:
for ($i=0; $b[$i]; $i++)
In general:
1. If you just want an obvious "is this thing set?", just
say things like:
if ($foo)
2. Don't do comparisons with undef. If you really need
to test the definedness of something (not something
you really need to do much as a beginner), say
something like:
if (defined $foo)
