3.7 File Maintenance Commands
mv [options] old_filename new_filename
-i interactive (prompt and wait for confirmation before proceeding)
-f don't prompt, even when copying over an existing target file (overrides -i)
% mv old_filename new_filename
You now have a file called new_filename and the file old_filename is gone. Actually all you've done is to update the directory table entry to give the file a new name. The contents of the file remain where they were.