I saw this bit of code on an old forum post:SSLRequire %{HTTP_HOST} =~ m\.secure\.powweb\.comAnd I was just wondering what the =~ and m ...  meant. I've been searching online and in the Apache documentation for any mention of the equal-sign tilde operator, but I've found no mention of it. I know that some directives can take a tilde to use a regular expression, but I've never seen the m ...  form used before.What exactly is that m ...  for? Where else would you see this form?
=~ (equal-sign tilde) and m ...  in .htaccess directive
apache;htaccess;httpd
That is used for matching a regex in a string.See man perlop:Binary =~ binds a scalar expression to a pattern match.  Certain         operations search or modify the string $_ by default.  This operator         makes that kind of operation work on some other string.  The right         argument is a search pattern, substitution, or transliteration.  The         left argument is what is supposed to be searched, substituted, or         transliterated instead of the default $_.andm/PATTERN/msixpogc         /PATTERN/msixpogc                 Searches a string for a pattern match, and in scalar context                 returns true if it succeeds, false if it fails.  If no string                 is specified via the =~ or !~ operator, the $_ string is                 searched.  (The string specified with =~ need not be an                 lvalue--it may be the result of an expression evaluation, but                 remember the =~ binds rather tightly.)  See also perlre.  See                 perllocale for discussion of additional considerations that                 apply when use locale is in effect.  ...  If / is the delimiter then the initial m is optional.  With                 the m you can use any pair of non-alphanumeric, non-                 whitespace characters as delimiters.