cp, mv, rmには-iオプションをデフォルトでエイリアスするとはかどる


man cp:

-i    Cause cp to write a prompt to the standard error output before copying a file that would overwrite an existing file.  If the response from the standard input begins with the character `y' or `Y', the file copy is attempted.  (The -i option overrides any previous -n option.)