Question

Please help make a regular expression to sites with or without paths,
for example:

http://www.sitename.domain/dir/dir2/file.jpg
www.sitename.domain/dir/file.jpg
sub.sitename.domain/dir/dir2/file.jpg
site.do/file.pjg
https://go.do/dir/file.png
ftp://site.dom/file.blah_blah

exact domains are not important

Answer 1

If you want to match a URL using regex, you could use this:

^(((https?)|(ftp)):\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([\/\w \.-]*)*\/?$

You can find some description on http://net.tutsplus.com/tutorials/other/8-regular-expressions-you-should-know/