rename from to file...
rename will rename the specified files by replacing the first occur- rence of from in their name by to. For example, given the files foo1, ..., foo9, foo10, ..., foo278, the commands rename foo foo0 foo? rename foo foo0 foo?? will turn them into foo001, ..., foo009, foo010, ..., foo278. And rename .htm .html *.htm will fix the extension of your html files.
mv(1) 1 January 2000 RENAME(1)