cssmerge is a command-line utility which extracts
selected blocks of CSS from one or more input
stylesheets, and merges them into a single
coherent output stylesheet, with optional comments
on where they came from, and warnings about
conflicting styles. Whole blocks can be chosen by
selector or partial blocks which contain a
particular property may be generated. Selectors
can be matched completely or by element, class, or
ID. Properties can be matched completely or
partially. The output is a valid CSS file, sorted
to make it easy to find what you are looking for.