http://www.perlmonks.org?node_id=996827


in reply to Re^2: Problem with regex passed to a hash
in thread Problem with regex passed to a hash

Yeah, Net::Telnet is rather old and uses a weird method of passing regexes as arguments. For a more recent module qr// would be appropriate, but Net::Telnet requires a string that starts and ends with a slash.

The other posters are right when they say you should double quote. Any method for building strings will work:

'/'.$username.'/' "/$username/" sprintf('/%s/', $username)
As an aside, if you're trying to log in, there's a login method in Net::Telnet.