refactor parallel code

openos/hostname.lua

@@ -0,0 +1,17 @@
+local os = _G.os
+
+local shell = require("openos.shell")
+local args = shell.parse(...)
+local hostname = args[1]
+
+if hostname then
+  os.setComputerLabel(hostname)
+else
+  hostname = os.getComputerLabel()
+  if hostname then
+    print(hostname)
+  else
+    io.stderr:write("Hostname not set\n")
+    return 1
+  end
+end