diff two css files to create an overriding css (e.g. for wordpress child themes)

diff -U99999 original.css modified.css | awk '/^-/{next} {f=f"\n"$0} /^\+.*[^ ]/{yes=1} /}/ {if(yes){print f} f="";yes=0}'
This will extract the differing CSS entries of two files. I've left the initial character (plus or space) in output to show the real differing line, remove the initial character to get a working CSS file. The output CSS file is usable by either adding it in a below the to original.css, or by only using the output but adding @import url("original.css"); in the beginning. This is very useful for converting Wordpress theme copies into real Wordpress child themes. Could exclude common lines within entries too, I guess, but that might not be worth the complexity.
Sample Output
+++ style.css	2012-01-12 08:33:13.486877866 +0100
@@ -1,1324 +1,1427 @@
 /* =Layout
 -------------------------------------------------------------- */
 LAYOUT: Two columns
 DESCRIPTION: Two-column fixed layout with one sidebar right of content
 #container {
 	float: left;
+	margin: 0 -240px 0 38px;
 	width: 100%;

 #content {
+	margin: 0 250px 0 0px;

By: unhammer
2012-01-12 07:57:22

What Others Think

Note: if there are lines that have been simply removed in "modified.css", use diff -U99999 original.css modified.css | awk '{f=f"\n"$0} /^[+-].*[^ ]/{yes=1} /}/ {if(yes){print f} f="";yes=0}' instead
unhammer · 510 weeks and 3 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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