How do I remove all files that match a pattern?

Use the find command (with care!)

find . -name '*.orig' #-delete

I've commented out the delete command but once you're happy with what it's matching, just remove the # from the line and it should delete all those files.

"find" has some very advanced techniques to search through all or current directories and rm files.

find ./ -name ".orig" -exec rm -rf {} \;

I have removed all files that starts with .nfs000000000 like this

rm .nfs000000000*