http://www.perlmonks.org?node_id=1016581


in reply to contextual substitution with s///?

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; ... }

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.