diff --git a/patch_flycast_memory.py b/patch_flycast_memory.py
index 04a75072..ced7da4f 100755
--- a/patch_flycast_memory.py
+++ b/patch_flycast_memory.py
@@ -1,39 +1,50 @@
 #!/bin/env python3
 
+import argparse
 import os
 import subprocess
 import sys
 
 
 def get_ip_address(ifname):
-  data = subprocess.check_output(['ifconfig', ifname])
-  for line in data.splitlines():
-    line = line.strip()
-    if line.startswith(b'inet '):
-      return line.split()[1].decode('ascii')
-  raise RuntimeError('cannot get address for interface ' + ifname)
+    data = subprocess.check_output(["ifconfig", ifname])
+    for line in data.splitlines():
+        line = line.strip()
+        if line.startswith(b"inet "):
+            return line.split()[1].decode("ascii")
+    raise RuntimeError("cannot get address for interface " + ifname)
 
 
 def main(argv):
-  if len(argv) < 2:
-    raise RuntimeError(f'Usage: {argv[0]} <original-destination> [new-destination]')
-  if os.geteuid() != 0:
-    raise RuntimeError('You must use sudo to run this script')
-  original_destination = argv[1]
-  new_destination = argv[2] if len(argv) > 2 else get_ip_address('en0')
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--pid", "-p", type=int, default=0)
+    parser.add_argument("orig_destination", type=str)
+    parser.add_argument("new_destination", type=str, default=None, nargs="?")
+    args = parser.parse_args()
 
-  print(f'Finding occurrences of \"{original_destination}\"')
-  addresses_str = subprocess.check_output(['memwatch', 'Flycast.app', 'find', f'\"{original_destination}\"'])
-  for line in addresses_str.splitlines():
-    # line is like '(0) 00007FFF038500A0 (rw-)' (we care only about the address)
-    tokens = line.split()
-    if len(tokens) != 3:
-      continue
-    print(f'Replacing \"{original_destination}\" with \"{new_destination}\" at {tokens[1]} in Flycast')
-    subprocess.check_call(['memwatch', 'Flycast.app', 'write', tokens[1], f'\"{new_destination}\" 00'])
+    if os.geteuid() != 0:
+        raise RuntimeError("You must use sudo to run this script")
+    new_destination = args.new_destination or get_ip_address("en0")
+    proc_arg = "Flycast.app" if args.pid == 0 else str(args.pid)
 
-  return 0
+    print(f'Finding occurrences of "{args.orig_destination}"')
+    addresses_str = subprocess.check_output(
+        ["memwatch", proc_arg, "find", f'"{args.orig_destination}"']
+    )
+    for line in addresses_str.splitlines():
+        # line is like '(0) 00007FFF038500A0 (rw-)' (we care only about the address)
+        tokens = line.split()
+        if len(tokens) != 3:
+            continue
+        print(
+            f'Replacing "{args.orig_destination}" with "{new_destination}" at {tokens[1]} in Flycast'
+        )
+        subprocess.check_call(
+            ["memwatch", proc_arg, "write", tokens[1], f'"{new_destination}" 00']
+        )
+
+    return 0
 
 
-if __name__ == '__main__':
-  sys.exit(main(sys.argv))
+if __name__ == "__main__":
+    sys.exit(main(sys.argv))