What choroba said. Your problem is the missing /m on the substitution so it only tries the first line in the string where it doesn't match.

If you want to split the line into space-separated fields later regardless of their meaning), couldn't you just use split /\s+/? When I have a task like this, I usually write a regex that captures a bunch of fields and ignores others, like this: 
my $re = qr{
    ^ (\S+ \s+ \S+ \s+ \S+) \s+ # time_stamp: Sep 18 00:00:58
    (\S+) \s+                   # host:       mailgate04
    [[:alpha:]]+/([[:alpha:]]+) # process:    postfix/smtp:
    \S+ \s+                     # PID:        [29259]:
    (.*)                        # rest
    }ox;
while(<$log>) {
   my ($time, $host, $rest) = /$re/o;
   ...
}

[download]

In case you're interested in the timestamp field and few other things, you could also think about a simple substr(). The spaces are there just to make it easy to work with fixed field widths.

In reply to Re: contextual substitution with s///? by mbethke
in thread contextual substitution with s///? by Wiggins

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