PERL Beginners - Regexp matching problems

Author

Regexp matching problems

Jason Price

2004-04-27, 12:26 am

I am having problems with one of my regexp substitutions not matching =
the first line returned in a set, and I'm having trouble figuring out =
why. I figure there's probably a hidden system character or something =
of the sort that is causing my regexp to fail.

Here's the scenario:

I'm forking off children from a parent, calling a remote script in each =
child. The remote script sends its results to STDOUT, which I'm =
capturing via pipes. The data from each child needs to be kept =
separate, so I'm prepending a tag to each line before printing to STDOUT =
($servers[$c] spits out the server name):

print "%%%%" . $servers[$c] . "%%%%" . $_;

Output from all children is captured into an array, and then split out =
into arrays based on each server name, removing the custom tag ($1 is =
the server name):

while(<READER> ) {
if ($_ =3D~ s/^%%%%(\w+)%%%%//) {
push @{$1}, $_;
}
}

I then proceed to format my output and print results on a per-server =
basis. The problem is that it appears that the first line returned to =
the parent array does not match my substitution regexp above, and the =
custom tag remains in place. Additionally, this only happens when more =
than one child process is spawned - with just one child, it works fine. =
Reading what I just wrote, maybe it's the first line returned from =
children finishing 2nd or later.

If I change the substitution regexp to:

if ($_ =3D~ s/^.*%%%%(\w+)%%%%//)

everything works perfectly. The only thing I can think of is that some =
system character is hiding between the ^ and my custom tag, but I can't =
seem to figure out what it is. Is there a way I can view system =
characters in a variable?

Probably not the best explanation, but hopefully that all makes sense. =
Any input as to what the issue might be, or how I might idendify or fix =
it?

Thanks.

Jason

Randy W. Sims

2004-04-27, 12:26 am

On 4/26/2004 4:27 PM, Price, Jason (TLR Corp) wrote:

> Is there a way I can view system characters in a variable?

my $str = "\n\r\bHello, World!\n";
printf( "%02x ", ord $_ ) for split //, $str;

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