Incredibly useful function that i've been using alot today to help move clients sites into a new server setup quickly using rysnc.
rsync is a software application and network protocol for Unix-like and Windows systems that synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate (thanks Wikipedia).
rsync -avz -e ssh username@yourotherserver:/pathto/domain/html/wp-content/plugins .
In this case I rsync the plugins folder into the current working directory (make sure if your copying and pasting this command to CD into the right folder first before running).
Trust me this will save you time!