What is the equals sign followed by tilde in lighttpd config (=~)?

Question

What is the difference between the following? Both work the same way from what I can tell/use it for

$HTTP["host"] =~ "a.domain.com" {
    server.document-root = "/var/www/a/"
}

$HTTP["host"] == "a.domain.com" {
    server.document-root = "/var/www/a/"
}

Would the =~ match x.a.domain.com?

From http://thomashunter.name/blog/subdomains-and-google-apps-with-gandi-and-linode/ *"The lighttpd configuration file uses a proprietary syntax (although it kinda looks like a cross between PHP and JSON). The Tilde Equal lines are a regular expression which match the requested domain name and apply the rules within that section."* — Robert Harvey, Feb 13 '13 at 22:19

score 2 · Accepted Answer · answered Feb 13 '13 at 22:30

The right-hand side of =~ is a regular expression.

x.a.domain.com would not match the regular expression a.domain.com.

Examples that would match:

axdomain.com
axdomainxcom
aydomainycom
a1domain1com
...

Is the example from a real-world example? It seems kinda pointless.

Something like this could be more meaningful:

$HTTP["host"] =~ ".*\.somedomain\.com" {
    server.document-root = "/var/www/somedomain.com/"
}

Meaning, serve all requests to *.somedomain.com from /var/www/somedomain.com/

This page has some more realistic examples with regex matching:

http://redmine.lighttpd.net/boards/2/topics/2518

What is the equals sign followed by tilde in lighttpd config (=~)?

1 Answers1