bug fixes

README.md

@@ -62,14 +62,14 @@ p = Popen(["./sftper", "--url", "sftp://localhost"],
 Sending commands:
 ```
 import json, os, struct
-dat = json.dumps({"command": "LISTDIR", "args":{"path", "/path"}}).encode()
-p.stdin.write(struct.pack('!I', len(dat), dat))
+dat = json.dumps({"command": "LISTDIR", "args":{"path": "/path"}}).encode()
+p.stdin.write(struct.pack('!I', len(dat)) + dat)
 ```
 
 Receiving results in Python
 ```
 import json, os, struct
-num = struct.unpack('!I', p.stdout.read(4))
+num = struct.unpack('!I', p.stdout.read(4))[0]
 dat = p.stdout.read(num)
 assert len(dat) == num
 zult = json.loads(dat)