Fix cli.py install-hysteria2

core/validator.py

@@ -0,0 +1,10 @@
+import os
+
+
+def validate_port(p:int)-> bool:
+    if p < 1 or p > 65535:
+        return False
+    # check if port is in use
+    if os.system(f'lsof -i:{p}') == 0:
+        return False
+    return True