diff --git a/copymac.py b/copymac.py
new file mode 100644
index 0000000..e9c5366
--- /dev/null
+++ b/copymac.py
@@ -0,0 +1,115 @@
+"""copymac.py -- Copy source files to/from Basilisk, with conversions."""
+from abc import ABCMeta, abstractmethod
+import os
+import pathlib
+import sys
+from dataclasses import dataclass
+from typing import Dict, List
+
+import xattr  # type: ignore
+
+SUBDIRS = ". macos sync lib".split()
+TEXT_SUFFIXES = ".c .h .r".split()
+TEXT_CREATOR = b"R*ch"  # BBEdit
+
+
+class Converter(metaclass=ABCMeta):
+    name: str
+
+    @abstractmethod
+    def convert(self, src: pathlib.Path, dest: pathlib.Path) -> None:
+        pass
+
+
+class TextConverter(Converter):
+    enc_in: str
+    enc_out: str
+    newline: str
+
+    name = "Text"
+
+    def __init__(self, enc_in: str, enc_out: str, newline: str) -> None:
+        self.enc_in = enc_in
+        self.enc_out = enc_out
+        self.newline = newline
+
+    def convert(self, src: pathlib.Path, dest: pathlib.Path) -> None:
+        text = src.read_text(encoding=self.enc_in)
+        lines = text.splitlines()
+        lines.append("")
+        dest.write_text(self.newline.join(lines), encoding=self.enc_out)
+
+
+class DataConverter(Converter):
+    name = "Data"
+
+    def convert(self, src: pathlib.Path, dest: pathlib.Path) -> None:
+        data = src.read_bytes()
+        dest.write_bytes(data)
+
+
+@dataclass
+class FileType:
+    converter: Converter
+    filetype: bytes
+    creator: bytes
+
+    def finder_info(self) -> bytes:
+        assert len(self.filetype) == 4
+        assert len(self.creator) == 4
+        return self.filetype + self.creator + b"\x01" + b"\x00" * 23
+
+
+def main(argv: List[str]) -> None:
+    if not argv:
+        print("Usage: python copymac.py (push|pull)", file=sys.stderr)
+        print("  pull: pull FROM guest (macintosh), into guest (unix)", file=sys.stderr)
+        print("  push: push TO guest (macintosh), from host (unix)", file=sys.stderr)
+        raise SystemExit(2)
+    unix_dir = pathlib.Path(__file__).resolve().parent
+    mac_dir = pathlib.Path(pathlib.Path.home(), "SyncFiles")
+    cmd = argv[0]
+
+    suffixes: Dict[str, FileType] = {}
+    text: Converter
+    data = DataConverter()
+    if cmd == "pull":
+        text = TextConverter("macintosh", "utf-8", "\n")
+        src_dir, dest_dir = mac_dir, unix_dir
+    elif cmd == "push":
+        text = TextConverter("utf-8", "macintosh", "\r")
+        src_dir, dest_dir = unix_dir, mac_dir
+    else:
+        print("Error: unknown command", file=sys.stderr)
+        raise SystemExit(2)
+
+    text_type = FileType(text, b"TEXT", TEXT_CREATOR)
+    for suffix in TEXT_SUFFIXES:
+        suffixes[suffix] = text_type
+    suffixes[".mcp"] = FileType(data, b"MMPr", b"CWIE")
+
+    for subdir in SUBDIRS:
+        src_subdir = src_dir / subdir
+        dest_subdir = dest_dir / subdir
+        dest_subdir.mkdir(exist_ok=True)
+        fset = set()
+        for src in src_subdir.iterdir():
+            print(src)
+            file_type = suffixes.get(src.suffix)
+            if file_type is not None:
+                fset.add(src.name)
+                print(file_type.converter.name, pathlib.Path(subdir, src.name))
+                dest = dest_subdir / src.name
+                file_type.converter.convert(src, dest)
+                if cmd == "push":
+                    info = file_type.finder_info()
+                    attr = xattr.xattr(dest)
+                    attr["com.apple.FinderInfo"] = info
+        for dest in dest_subdir.iterdir():
+            if dest.suffix in suffixes and not dest.name in fset:
+                print("Delete", pathlib.Path(subdir, dest.name))
+                dest.unlink()
+
+
+if __name__ == "__main__":
+    main(sys.argv[1:])