rename — Rename files
rename from to file...
rename will
rename the specified files by replacing the first occurrence
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.