From: Tom Allison <tallison@...>
Date: 2006-10-03T09:01:23+09:00
Subject: regular expressions

I'm sorry if this has been done before, but I can't seem to find any good examples:

I'm trying to search mail messages for headers based on the following:

config = YAML.load_file('config.yaml')

$stdin.each do |line|
   puts line if line =~ /^Recevied:/ .. line =~ /by #{config['hostname']}/o
end

and guess what?  It doesn't work.
If I hard code the hostname it works fine.
But this and /by config['hostname']/ both fail to match.

So, how do you set a variable in a regular expression?

Also, how would I match multiple lines?

I would much rather match something like:

/^Received:.+?\s{4,}by #{config['hostname']}/sm
because that will pick up the one Received header I want.
I can write in Perl 5 regex but I'm not as familiar with Ruby's methods.