Q: Regular expression to remove CSS comments I want to write the regular expression in php for matching the line within a double and single quotes. Actually I am writing the code for removing comment lines in css file.
Like:
"/* I don't want to remove this line */"

but
/* I want to remove this line */

Eg:
- valid code /* comment */ next valid code "/* not a comment */" /* this is comment */

Expected result:   
- valid code next valid code "/* not a comment */"

Please any one give me a regular expression in php for my requirement.

A: The following should do it:
preg_replace( '/\s*(?!<\")\/\*[^\*]+\*\/(?!\")\s*/' , '' , $theString );

Test case:
$theString = '- valid code /* comment */ next valid code "/* not a comment */" /* this is comment */';

preg_replace( '/(?!<\")\/\*[^\*]+\*\/(?!\")/' , ' ' , $theString );

# Returns 'valid code next valid code "/* not a comment */" '

Revision : 28 Nov 2014
As per comments from @hexalys, who referred to http://www.catswhocode.com/blog/3-ways-to-compress-css-files-using-php
The updated regular expression, as per that article, is:
preg_replace( '!/\*[^*]*\*+([^/][^*]*\*+)*/!' , '' , $theString );

