Ask Gemini Pro 2.5 to build the rsync command and then give it the man page for your version of rsync. It should succeed the first time.

Here's a command to copy the man page to the clipboard than you can immediately paste into aistudio (on a Mac):

    man rsync | col -b | pbcopy

As a general rule, if you would need to look something up to complete a task, the AI needs the same information you do—but it's your job to provide it.