try this without quotes. Rsync has be to on both machines. Also if you want to automate this using a shell script then you'll need to create a public/private keypair using ssh in order to do a passwordless login.
"rsync -arz --delete -e ssh bob@someserver.com:/copy/this/directory /copy/to/this/directory"
and if you want to see every file your are copying add a v
like this
"rsync -arzv --delete -e ssh bob@someserver.com:/copy/this/directory /copy/to/this/directory"
and if you want to check how much space the entire copy uses
"du -ch /copy/to/this/directory"