One-line CSS minifier

CSS minification in one line:

$ cat sourcefile.css | sed -e 's/^[ \t]*//g; s/[ \t]*$//g; s/\([:{;,]\) /\1/g; s/ {/{/g; s/\/\*.*\*\///g; /^$/d' | sed -e :a -e '$!N; s/\n\(.\)/\1/; ta' >target.css

With comments:

$ cat sourcefile.css | sed -e '
s/^[ \t]*//g;         # remove leading space
s/[ \t]*$//g;         # remove trailing space
s/\([:{;,]\) /\1/g;   # remove space after a colon, brace, semicolon, or comma
s/ {/{/g;             # remove space before a semicolon
s/\/\*.*\*\///g;      # remove comments
/^$/d                 # remove blank lines
' | sed -e :a -e '$!N; s/\n\(.\)/\1/; ta # remove all newlines
' > target.css

Using this script, I was able to chop about 29% (10K) off our master.css file. Assumes lines end in semicolons that should end in semicolons. May not play well with certain freakish outdated CSS hacks. Use at your own risk, and always test throughly before releasing into the wild.