Regex to remove line from css file

Question

I'm trying to remove include statements from a css file. So given a css file like

@import url("css1.css");
@import url("css2.css");
@import url("css3.css");
.myfirstclass {color:red}

after I run the command I want to be

.myfirstclass {color:red}

This is the command I am using but it isn't working. Is there a way to do this?

$css_file = preg_replace("/^@import url(.*)$/", "", $css_file);

Is every import in the css file terminated with a linebreak of some sort? Meaning, its not a .min'ified .css file? — IncredibleHat
– IncredibleHat, Commented Feb 10, 2018 at 14:34
The parentheses need \escaping else they are a capture group — Alex K.
– Alex K., Commented Feb 10, 2018 at 14:35
Also, there might be whitespace before the @, and dont forget the semicolon... I'm not a wiz with regex patterns, so it would take me way too long to figure it out when i know a regexpert will pop in and solve this riddle in a flash! :) — IncredibleHat
– IncredibleHat, Commented Feb 10, 2018 at 14:37
You forgot m modifier $css_file = preg_replace("/^\s*@import url.*/m", "", $css_file); — revo
– revo, Commented Feb 10, 2018 at 14:37
@AlexK The unescaped parentheses does not make the pattern fail, it just makes the pattern less literal. It would effectively just create a capture group which contains the substring from ( to ;. The faulty component is the $. Either add the m flag or remove the $. Or best, use revo's second method. — mickmackusa
– mickmackusa ♦, Commented Feb 12, 2018 at 1:20

revo · Accepted Answer · 2018-02-10 14:52:42Z

2

Caret ^ alongside dollar sign $ mean asserting start of input string and end of it respectively unless m flag is set. You also need to check for spaces in beginning of line and match linebreaks at end:

$css_file = preg_replace("/^\s*@import url.*\R*/m", "", $css_file);  
                             ^               ^  ^

In case of working with minified CSS:

$css_file = preg_replace("/@import[^;]+;/", "", $css_file);

edited Feb 10, 2018 at 14:52

answered Feb 10, 2018 at 14:46

revo

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2 Comments

user3052443 Over a year ago

Thank you. This worked great. But please explain what the R is for. I can't find it mentioned in my searches for it. From your text, it seems it might refer to the line break but examples I found sayo to use \r\n.

revo Over a year ago

\R means any kind of linebreaks which includes Unicode linebreaks as well.

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