[ILUG] Perl RE question

[Niall O Broin]

I have a list of numbers in a string like


123,456,789

and I need to find out if any of them begin with 9. This seemed correct

#!/usr/bin/perl
$numlist = $ARGV[0];
if ($numlist =~ /[,^]9/) {
  print "$numlist matched\n"
} else {
  print "$numlist didn't match\n"
}

but it doesn't work. Now, I have solved my problem. It's Perl, and TIMTOWTDI
as we Perlmongers say. I could have split the string, but I chose to do

if (",$numlist" =~ /,9/)

which works fine. But why won't my program above work ? I had started off
with 

if ($numlist =~ /[^,]9/)

but realised (in time, believe it or not) that this was of course a negating
character class. I tried escaping the ^ before I RTFM and simply made the ^
not the first character, as TFM says to do. I also tried \A instead of ^ but
although this works outside of a character class, it does not work as above.

I just tried this with grep too. Given a file, nums, with these lines

123,987 - MATCH
123,456 - NO MATCH
987,123 - MATCH

I think that  grep "[,^]9" nums    should match the lines marked MATCH but
it doesn't.  egrep ",9|^9" nums  does match the lines marked MATCH so why
the hell doesn't the alternation work ? What is wrong with my interpretation
of both the grep and the Perl manuals ? (The alternative is that they're
both wrong, and that seems passing unlikely).



Regards,



Niall