gistfile1.txt

root@vagrant:~# hhvm hello.hh

Fatal error: /root/hello.hh appears to be a Hack file, but you do not appear to be running the Hack typechecker. See the documentation at http://docs.hhvm.com/manual/en/install.hack.bootstrapping.php for information on getting it running. You can also set Hack.Lang.LookForTypechecker=0 to disable this check (not recommended).
root@vagrant:~# mv hello.hh hello.^C
root@vagrant:~# vi ..hhconfig^C
root@vagrant:~# vi .hhconfig
root@vagrant:~# touch .hhconfig
root@vagrant:~# hh_client
Server launched for /root
Spawned hh_server (child pid=22984)
Logs will go to /tmp/hh_server_root/root-zSroot.log
^Z
[1]+  Stopped                 hh_client
root@vagrant:~# bg
[1]+ hh_client &
root@vagrant:~# No errors!

[1]+  Done                    hh_client
root@vagrant:~# hhvm hello.hh
Hello, world!root@vagrant:~#