Linux
rsync builder
Choose source, destination and options and get the rsync command, with a plain English explanation below each part.
What does this mean?
rsync copies and synchronizes files, locally or to another computer via SSH. After the first time, only changes are transferred, so it is ideal for backups. Choose what you want above; you will get the command and below each part in plain English what it does.
Always start with a dry run (-n), especially with --delete. The command is composed in your browser; nothing is sent. More: the rsync cheat sheet and backups with the 3-2-1 rule.