### macOS 10.11、10.12
sudo killall -HUP mDNSResponder
OS X 10.10 Yosemite
sudo discoveryutil mdnsflushcache;sudo discoveryutil udnsflushcaches;say flushed
OS X 10.9 Mavericks
dscacheutil -flushcache;sudo killall -HUP mDNSResponder
OS X Lion (10.7) 和 OS X Mountain Lion (10.8)
‘sudo killall -HUP mDNSResponder’
OS X 10.3 和 10.4 Tiger
‘lookupd -flushcache’
