Use rsync instead of mv when you need to move a large amount of data, for example to an external storage device.

Unlike a standard mv command, which often leaves you staring at a hanging cursor, rsync (especially with the -v flag) provides real-time visibility by logging each file as it transfers.

Moving files is just the beginning, however. rsync shines when keeping two directories in sync, with one being the source and one the target. It quickly resolves delta and thus can be used as a backup tool

AWS has copied this command (in spirit) with aws s3 sync, which I use as an easy way to backup local directories to the cloud.

rsync Hello World

rsync -av ./01/ ./02/

This command copies the contents of 01 dir into 02. The trailing slash (as with other unix-style commands) means “the contents of” the preceding directory. -a is archive mode, which means “just bring over everything” including sym links, permissions, group settings, etc.

This version does a dry run, and also shows the progress of each file:

rsync -avP ./01/ ./02/