etcdctl*.1 to etcdctl3*.1
for line in $(ls *.1); do mv $line $(echo $line | sed "s/etcdctl/etcdctl3/"); done
rename refs in man pages
sed -i "s/\\\fBetcdctl\\\-/\\\fBetcdctl3\\\-/g" *.1
sed -i s"/^etcdctl/ETCDCTL=3 etcdctl/" etcdctl3*.1
etcdctl*.1 to etcdctl2*.1
sed -i "s/\\\fBetcdctl-/\\\fBetcdctl2-/g" *.1