ip – show / manipulate routing, network devices, interfaces and tunnels

ip addr
ip route show

du – estimate file space usage

du --max-depth=1 --human-readable --one-file-system Documents/
du -hxd 1 Documents/

rsync – a fast, versatile, remote (and local) file-copying tool

rsync -avz --update -e ssh --progress --delete leopardb@neptune:/home/leopardb/Documents/ /home/leopardb/Documents/ --dry-run
rsync -avz --update -e ssh --progress --delete leopardb@neptune:/home/leopardb/Documents/ /home/leopardb/Documents/