Check out the perlre man page, which explains in good detail how to work with regex.

When using characters that are normally interpreted as syntax, in your case (/ and .) these characters must be escaped. To have a slash (/) represent a slash literally, you designate the character to be escaped by adding a backslash in front of it like so (\/). This tells perl to interpret the slash / literally. The same is true of the period (\.) and other characters that are normally used as perl syntax.

Hope this helps!