diff --git a/shelephant/cli.py b/shelephant/cli.py
index cf16a3c..2ff7def 100644
--- a/shelephant/cli.py
+++ b/shelephant/cli.py
@@ -809,6 +809,7 @@ class MyFmt(
         "mv",
         "rm",
         "pwd",
+        "diff",
         "gitignore",
         "add",
         "remove",
@@ -841,6 +842,8 @@ def _shelephant_main():
         dataset.rm(sys.argv[2:])
     elif args.command == "pwd":
         dataset.pwd(sys.argv[2:])
+    elif args.command == "diff":
+        dataset.diff(sys.argv[2:])
     elif args.command == "gitignore":
         dataset.gitignore(sys.argv[2:])
     elif args.command == "add":
diff --git a/shelephant/dataset.py b/shelephant/dataset.py
index 3b1bbc2..244ce52 100644
--- a/shelephant/dataset.py
+++ b/shelephant/dataset.py
@@ -1648,6 +1648,62 @@ def pwd(args: list[str]):
         print(os.path.relpath(root / post, os.getcwd()))
 
 
+def _diff_parser():
+    """
+    Return parser for :py:func:`shelephant diff`.
+    """
+
+    desc = textwrap.dedent(
+        """
+        Show differences between two storage locations.
+        """
+    )
+
+    class MyFmt(
+        argparse.RawDescriptionHelpFormatter,
+        argparse.ArgumentDefaultsHelpFormatter,
+        argparse.MetavarTypeHelpFormatter,
+    ):
+        pass
+
+    parser = argparse.ArgumentParser(formatter_class=MyFmt, description=desc)
+
+    parser.add_argument("--version", action="version", version=version)
+    parser.add_argument("--colors", type=str, default="dark", help="Color scheme [none, dark].")
+    parser.add_argument("--pop", type=str, action="append", help='Pop direction (e.g. "==").')
+    parser.add_argument("source", type=str, help="Storage location.")
+    parser.add_argument("dest", type=str, help="Storage location.")
+    return parser
+
+
+def diff(args: list[str]):
+    """
+    Command-line tool, see ``--help``.
+
+    :param args: Command-line arguments (should be all strings).
+    """
+
+    parser = _diff_parser()
+    args = parser.parse_args(args)
+    sdir = _search_upwards_dir(".shelephant")
+    assert sdir is not None, "Not in a shelephant dataset"
+
+    with search.cwd(sdir):
+        storage = yaml.read(sdir / "storage.yaml")
+        assert args.source in storage, f"Unknown storage location {args.source}"
+        assert args.dest in storage, f"Unknown storage location {args.dest}"
+        source = Location.from_yaml(f"storage/{args.source}.yaml")
+        dest = Location.from_yaml(f"storage/{args.dest}.yaml")
+
+    status = source.diff(dest)
+    if args.pop is not None:
+        for i in args.pop:
+            status.pop(i)
+    for key in status:
+        status[key] = sorted(status[key])
+    output.diff(status, colors=args.colors)
+
+
 def _status_parser():
     """
     Return parser for :py:func:`shelephant status`.
diff --git a/shelephant/output.py b/shelephant/output.py
index 2551899..5521a26 100644
--- a/shelephant/output.py
+++ b/shelephant/output.py
@@ -162,3 +162,99 @@ def copyplan(
         return sio.getvalue()
 
     autoprint(sio.getvalue())
+
+
+def diff(
+    status: dict[list[str]],
+    colors: str = "none",
+    display: bool = True,
+    max_align: int = 80,
+) -> str:
+    """
+    Print copy plan.
+
+    :param status:
+        Dictionary of status. E.g.::
+
+            {
+                '==' : ['file4'],
+                '?=' : [],
+                '!=' : ['file3'],
+                '->' : ['file1', 'file2'],
+                '<-' : [],
+            }
+
+    :param colors: Color theme name, see :py:func:`theme`.
+    :param display: Display output (``False``: return as string).
+    :param max_align: Maximum width of the first column.
+    :return: Output string (if ``display=False``).
+    """
+    color = _theme(colors.lower())
+    sio = io.StringIO()
+
+    skip = status.pop("==", [])
+    right = status.pop("->", [])
+    left = status.pop("<-", [])
+    ne = status.pop("!=", [])
+    na = status.pop("?=", [])
+
+    if len(ne) + len(na) + len(left) + len(right) + len(skip) == 0:
+        return
+
+    width = max(len(file) for file in ne + na + left + right + skip)
+    width = min(width, max_align)
+
+    for file in ne:
+        print(
+            "{:s} {:s} {:s}".format(
+                _format(file, width=width, color=color["overwrite"]),
+                _format("!=", color=color["bright"]),
+                _format(file, color=color["overwrite"]),
+            ),
+            file=sio,
+        )
+
+    for file in na:
+        print(
+            "{:s} {:s} {:s}".format(
+                _format(file, width=width, color=color["overwrite"]),
+                _format("?=", color=color["bright"]),
+                _format(file, color=color["overwrite"]),
+            ),
+            file=sio,
+        )
+
+    for file in left:
+        print(
+            "{:s} {:s} {:s}".format(
+                _format(file, width=width, color=color["new"]),
+                _format("<-", color=color["bright"]),
+                _format(file, color=color["bright"]),
+            ),
+            file=sio,
+        )
+
+    for file in right:
+        print(
+            "{:s} {:s} {:s}".format(
+                _format(file, width=width, color=color["bright"]),
+                _format("->", color=color["bright"]),
+                _format(file, color=color["new"]),
+            ),
+            file=sio,
+        )
+
+    for file in skip:
+        print(
+            "{:s} {:s} {:s}".format(
+                _format(file, width=width, color=color["skip"]),
+                _format("==", color=color["skip"]),
+                _format(file, color=color["skip"]),
+            ),
+            file=sio,
+        )
+
+    if not display:
+        return sio.getvalue()
+
+    autoprint(sio.getvalue())
diff --git a/tests/test_dataset.py b/tests/test_dataset.py
index 3122fbf..d36b8bb 100644
--- a/tests/test_dataset.py
+++ b/tests/test_dataset.py
@@ -219,6 +219,20 @@ def test_basic(self):
             ret = _plain(sio.getvalue())[1:]
             self.assertEqual(ret, expect)
 
+            with cwd(dataset), contextlib.redirect_stdout(io.StringIO()) as sio:
+                shelephant.dataset.diff(["--colors", "none", "source1", "source2"])
+
+            expect = [
+                "e.txt <- e.txt",
+                "f.txt <- f.txt",
+                "c.txt -> c.txt",
+                "d.txt -> d.txt",
+                "a.txt == a.txt",
+                "b.txt == b.txt",
+            ]
+            ret = _plain(sio.getvalue())
+            self.assertEqual(ret, expect)
+
             with cwd(dataset):
                 for f in ["a.txt", "b.txt", "c.txt", "d.txt"]:
                     self.assertEqual(pathlib.Path(f).readlink().parent.name, "source1")