Do not prompt for confirmation before overwriting the destination path. (The -f option overrides any previous -i or -n options.)
Cause mv to write a prompt to standard error before moving a file that would overwrite an existing file. If the response from the standard input begins with the character y or Y, the move is attempted. (The -i option overrides any previous -f or -n options.)
Do not overwrite an existing file. (The -n option overrides any previous -f or -i options.)
Cause mv to be verbose, showing files after they are moved.
It is an error for either the source operand or the destination path to specify a directory unless both do.
If the destination path does not have a mode which permits writing, mv prompts the user for confirmation as specified for the -i option.
As the rename(2) call does not work across file systems, mv uses cp(1) and rm(1) to accomplish the move. The effect is equivalent to:
rm -f destination_path && \
cp -pRP source_file destination && \
rm -rf source_file