diff --git a/Justfile b/Justfile
index 05140c0..de0712a 100644
--- a/Justfile
+++ b/Justfile
@@ -13,6 +13,7 @@ clean:
 
 fmt:
     cargo fmt
+    git ls-files | grep '\.py$' | xargs isort
     git ls-files | grep '\.py$' | xargs black
     git ls-files | grep '\.sh$' | xargs -L 1 shfmt --indent 4 --write
 
@@ -23,6 +24,7 @@ fmt-check:
 
 lint:
     cargo clippy --no-deps -- -Dwarnings
+    git ls-files | grep '\.py$' | xargs ruff --ignore E501
     git ls-files | grep '\.sh$' | xargs -L 1 shellcheck --norc
 
 lint-fix:
diff --git a/depcheck/update-cargo-dependencies.py b/depcheck/update-cargo-dependencies.py
index e69e74d..7b5145f 100755
--- a/depcheck/update-cargo-dependencies.py
+++ b/depcheck/update-cargo-dependencies.py
@@ -1,9 +1,8 @@
 #!/usr/bin/env python3
 
-import subprocess
-import os
 import json
-import sys
+import os
+import subprocess
 
 import semver
 import tomlkit
diff --git a/docs/src/developing.md b/docs/src/developing.md
index 33eb147..df32a6f 100644
--- a/docs/src/developing.md
+++ b/docs/src/developing.md
@@ -34,8 +34,8 @@ You will need the following tools:
   [here](https://github.com/casey/just#installation) for installation
   instructions (it's most likely just a simple `cargo install just`).
 * Docker & docker-compose for the e2e tests
-* `black` and `shfmt` for formatting.
-* `shellcheck` for shell script linting
+* `isort`, `black` and `shfmt` for formatting.
+* `ruff` and `shellcheck` for linting.
 * `mdbook` for the documentation
 
 Here are the tools:
diff --git a/docs/src/local_configuration.md b/docs/src/local_configuration.md
index 6cbcea3..35042ad 100644
--- a/docs/src/local_configuration.md
+++ b/docs/src/local_configuration.md
@@ -11,7 +11,7 @@ Let's try it out:
 ## Get the example configuration
 
 ```bash
-$ curl --proto '=https' --tlsv1.2 -sSfO https://raw.githubusercontent.com/hakoerber/git-repo-manager/master/example.config.toml
+curl --proto '=https' --tlsv1.2 -sSfO https://raw.githubusercontent.com/hakoerber/git-repo-manager/master/example.config.toml
 ```
 
 Then, you're ready to run the first sync. This will clone all configured
@@ -30,7 +30,7 @@ $ grm repos sync config --config example.config.toml
 
 If you run it again, it will report no changes:
 
-```
+```bash
 $ grm repos sync config -c example.config.toml
 [✔] git-repo-manager: OK
 [✔] dotfiles: OK
@@ -43,11 +43,18 @@ write a configuration from scratch. Luckily, GRM has a way to generate a
 configuration from an existing file tree:
 
 ```bash
-$ grm repos find local ~/your/project/root > config.toml
+grm repos find local ~/your/project/root > config.toml
 ```
 
 This will detect all repositories and remotes and write them to `config.toml`.
 
+You can exclude repositories from the generated configuration by providing
+a regex that will be test against the path of each discovered repository:
+
+```bash
+grm repos find local ~/your/project/root --exclude "^.*/subdir/match-(foo|bar)/.*$" > config.toml
+```
+
 ### Show the state of your projects
 
 ```bash
@@ -65,7 +72,7 @@ $ grm repos status --config example.config.toml
 You can also use `status` without `--config` to check the repository you're
 currently in:
 
-```
+```bash
 $ cd ~/example-projects/dotfiles
 $ grm repos status
 ╭──────────┬──────────┬────────┬──────────┬───────┬─────────╮
@@ -79,5 +86,5 @@ $ grm repos status
 
 By default, the repo configuration uses TOML. If you prefer YAML, just give it a
 YAML file instead (file ending does not matter, `grm` will figure out the
-format).  For generating a configuration, pass `--format yaml` to `grm repo
+format). For generating a configuration, pass `--format yaml` to `grm repo
 find` which generates a YAML configuration instead of a TOML configuration.
diff --git a/docs/src/testing.md b/docs/src/testing.md
index c3c2c4c..4dcedad 100644
--- a/docs/src/testing.md
+++ b/docs/src/testing.md
@@ -49,7 +49,7 @@ Note: You will most likely not need to read this.
 Each test parameter will exponentially increase the number of tests that will be
 run. As a general rule, comprehensiveness is more important than test suite
 runtime (so if in doubt, better to add another parameter to catch every edge
-case). But try to keep the total runtime sane. Currently, the whole `just e2e`
+case). But try to keep the total runtime sane. Currently, the whole `just test-e2e`
 target runs ~8'000 tests and takes around 5 minutes on my machine, exlucding
 binary and docker build time. I'd say that keeping it under 10 minutes is a good
 idea.
diff --git a/e2e_tests/conftest.py b/e2e_tests/conftest.py
index 0c23ab6..ef201e1 100644
--- a/e2e_tests/conftest.py
+++ b/e2e_tests/conftest.py
@@ -1,7 +1,5 @@
 import os
 
-from helpers import *
-
 
 def pytest_configure(config):
     os.environ["GIT_AUTHOR_NAME"] = "Example user"
diff --git a/e2e_tests/docker-rest/flask/app.py b/e2e_tests/docker-rest/flask/app.py
index e22c533..3d00e54 100644
--- a/e2e_tests/docker-rest/flask/app.py
+++ b/e2e_tests/docker-rest/flask/app.py
@@ -3,5 +3,5 @@ from flask import Flask
 app = Flask(__name__)
 app.url_map.strict_slashes = False
 
-import github
-import gitlab
+import github  # noqa: E402,F401
+import gitlab  # noqa: E402,F401
diff --git a/e2e_tests/docker-rest/flask/github.py b/e2e_tests/docker-rest/flask/github.py
index e51df42..6d1659d 100644
--- a/e2e_tests/docker-rest/flask/github.py
+++ b/e2e_tests/docker-rest/flask/github.py
@@ -1,10 +1,8 @@
 import os.path
 
-from app import app
-
-from flask import Flask, request, abort, jsonify, make_response
-
 import jinja2
+from app import app
+from flask import abort, jsonify, make_response, request
 
 
 def check_headers():
@@ -48,7 +46,7 @@ def add_pagination(response, page, last_page):
 
 def read_project_files(namespaces=[]):
     last_page = 4
-    page = username = int(request.args.get("page", "1"))
+    page = int(request.args.get("page", "1"))
     response_file = f"./github_api_page_{page}.json.j2"
     if not os.path.exists(response_file):
         return jsonify([])
diff --git a/e2e_tests/docker-rest/flask/gitlab.py b/e2e_tests/docker-rest/flask/gitlab.py
index bbfb26e..605a57d 100644
--- a/e2e_tests/docker-rest/flask/gitlab.py
+++ b/e2e_tests/docker-rest/flask/gitlab.py
@@ -1,10 +1,8 @@
 import os.path
 
-from app import app
-
-from flask import Flask, request, abort, jsonify, make_response
-
 import jinja2
+from app import app
+from flask import abort, jsonify, make_response, request
 
 
 def check_headers():
@@ -48,7 +46,7 @@ def add_pagination(response, page, last_page):
 
 def read_project_files(namespaces=[]):
     last_page = 4
-    page = username = int(request.args.get("page", "1"))
+    page = int(request.args.get("page", "1"))
     response_file = f"./gitlab_api_page_{page}.json"
     if not os.path.exists(response_file):
         return jsonify([])
diff --git a/e2e_tests/helpers.py b/e2e_tests/helpers.py
index b9567e6..e54a15f 100644
--- a/e2e_tests/helpers.py
+++ b/e2e_tests/helpers.py
@@ -1,12 +1,12 @@
 #!/usr/bin/env python3
 
+import hashlib
+import inspect
 import os
 import os.path
+import shutil
 import subprocess
 import tempfile
-import hashlib
-import shutil
-import inspect
 
 import git
 
@@ -176,7 +176,6 @@ class TempGitRemote:
             newobj.remoteid = remoteid
             return newobj, remoteid
         else:
-            refresh = False
             if cachekey not in cls.obj:
                 tmpdir = get_temporary_directory()
                 shell(
diff --git a/e2e_tests/test_basic.py b/e2e_tests/test_basic.py
index 6ea5172..dcfd95e 100644
--- a/e2e_tests/test_basic.py
+++ b/e2e_tests/test_basic.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 
-from helpers import *
+from helpers import grm
 
 
 def test_invalid_command():
diff --git a/e2e_tests/test_repos_find.py b/e2e_tests/test_repos_find.py
index 59b0078..1b35668 100644
--- a/e2e_tests/test_repos_find.py
+++ b/e2e_tests/test_repos_find.py
@@ -1,12 +1,13 @@
 #!/usr/bin/env python3
 
+import os
+import re
 import tempfile
 
-import toml
 import pytest
+import toml
 import yaml
-
-from helpers import *
+from helpers import NonExistentPath, TempGitRepository, grm, shell
 
 
 def test_repos_find_nonexistent():
@@ -63,9 +64,10 @@ def test_repos_find_non_git_repos():
         assert len(cmd.stderr) != 0
 
 
-@pytest.mark.parametrize("default", [True, False])
+@pytest.mark.parametrize("default_format", [True, False])
 @pytest.mark.parametrize("configtype", ["toml", "yaml"])
-def test_repos_find(configtype, default):
+@pytest.mark.parametrize("exclude", [None, "^.*/repo2$", "^not_matching$"])
+def test_repos_find(configtype, exclude, default_format):
     with tempfile.TemporaryDirectory() as tmpdir:
         shell(
             f"""
@@ -99,13 +101,19 @@ def test_repos_find(configtype, default):
         )
 
         args = ["repos", "find", "local", tmpdir]
-        if not default:
+        if not default_format:
             args += ["--format", configtype]
+        if exclude:
+            args += ["--exclude", exclude]
         cmd = grm(args)
         assert cmd.returncode == 0
-        assert len(cmd.stderr) == 0
+        if exclude == "^.*/repo2$":
+            assert re.match(r"^.*\[skipped\] .*\/repo2$", cmd.stderr.lower())
+            assert "repo2" in cmd.stderr.lower()
+        else:
+            assert len(cmd.stderr) == 0
 
-        if default or configtype == "toml":
+        if default_format or configtype == "toml":
             output = toml.loads(cmd.stdout)
         elif configtype == "yaml":
             output = yaml.safe_load(cmd.stdout)
@@ -120,7 +128,7 @@ def test_repos_find(configtype, default):
             assert set(tree.keys()) == {"root", "repos"}
             assert tree["root"] == tmpdir
             assert isinstance(tree["repos"], list)
-            assert len(tree["repos"]) == 2
+            assert len(tree["repos"]) == (1 if exclude == "^.*/repo2$" else 2)
 
             repo1 = [r for r in tree["repos"] if r["name"] == "repo1"][0]
             assert repo1["worktree_setup"] is False
@@ -137,30 +145,33 @@ def test_repos_find(configtype, default):
             assert someremote["type"] == "ssh"
             assert someremote["url"] == "ssh://example.com/repo2.git"
 
-            repo2 = [r for r in tree["repos"] if r["name"] == "repo2"][0]
-            assert repo2["worktree_setup"] is False
-            assert isinstance(repo1["remotes"], list)
-            assert len(repo2["remotes"]) == 1
+            if exclude == "^.*/repo2$":
+                assert [r for r in tree["repos"] if r["name"] == "repo2"] == []
+            else:
+                repo2 = [r for r in tree["repos"] if r["name"] == "repo2"][0]
+                assert repo2["worktree_setup"] is False
+                assert isinstance(repo1["remotes"], list)
+                assert len(repo2["remotes"]) == 1
 
-            origin = [r for r in repo2["remotes"] if r["name"] == "origin"][0]
-            assert set(origin.keys()) == {"name", "type", "url"}
-            assert origin["type"] == "https"
-            assert origin["url"] == "https://example.com/repo2.git"
+                origin = [r for r in repo2["remotes"] if r["name"] == "origin"][0]
+                assert set(origin.keys()) == {"name", "type", "url"}
+                assert origin["type"] == "https"
+                assert origin["url"] == "https://example.com/repo2.git"
 
 
-@pytest.mark.parametrize("default", [True, False])
+@pytest.mark.parametrize("default_format", [True, False])
 @pytest.mark.parametrize("configtype", ["toml", "yaml"])
-def test_repos_find_in_root(configtype, default):
+def test_repos_find_in_root(configtype, default_format):
     with TempGitRepository() as repo_dir:
 
         args = ["repos", "find", "local", repo_dir]
-        if not default:
+        if not default_format:
             args += ["--format", configtype]
         cmd = grm(args)
         assert cmd.returncode == 0
         assert len(cmd.stderr) == 0
 
-        if default or configtype == "toml":
+        if default_format or configtype == "toml":
             output = toml.loads(cmd.stdout)
         elif configtype == "yaml":
             output = yaml.safe_load(cmd.stdout)
@@ -194,8 +205,8 @@ def test_repos_find_in_root(configtype, default):
 
 
 @pytest.mark.parametrize("configtype", ["toml", "yaml"])
-@pytest.mark.parametrize("default", [True, False])
-def test_repos_find_with_invalid_repo(configtype, default):
+@pytest.mark.parametrize("default_format", [True, False])
+def test_repos_find_with_invalid_repo(configtype, default_format):
     with tempfile.TemporaryDirectory() as tmpdir:
         shell(
             f"""
@@ -229,13 +240,13 @@ def test_repos_find_with_invalid_repo(configtype, default):
         )
 
         args = ["repos", "find", "local", tmpdir]
-        if not default:
+        if not default_format:
             args += ["--format", configtype]
         cmd = grm(args)
         assert cmd.returncode == 0
         assert "broken" in cmd.stderr
 
-        if default or configtype == "toml":
+        if default_format or configtype == "toml":
             output = toml.loads(cmd.stdout)
         elif configtype == "yaml":
             output = yaml.safe_load(cmd.stdout)
diff --git a/e2e_tests/test_repos_find_remote.py b/e2e_tests/test_repos_find_remote.py
index df395f8..bc3983e 100644
--- a/e2e_tests/test_repos_find_remote.py
+++ b/e2e_tests/test_repos_find_remote.py
@@ -1,14 +1,13 @@
 #!/usr/bin/env python3
 
-import re
 import os
+import re
+import tempfile
 
-import toml
 import pytest
+import toml
 import yaml
-
-from helpers import *
-
+from helpers import grm
 
 ALTERNATE_DOMAIN = os.environ["ALTERNATE_DOMAIN"]
 PROVIDERS = ["github", "gitlab"]
@@ -275,9 +274,9 @@ def test_repos_find_remote_user(
                 if not worktree_default:
                     cfg += f"worktree = {str(worktree).lower()}\n"
                 if force_ssh:
-                    cfg += f"force_ssh = true\n"
+                    cfg += "force_ssh = true\n"
                 if override_remote_name:
-                    cfg += f'remote_name = "otherremote"\n'
+                    cfg += 'remote_name = "otherremote"\n'
                 if use_owner:
                     cfg += """
                         [filters]
@@ -475,7 +474,7 @@ def test_repos_find_remote_group(
                 if not worktree_default:
                     cfg += f"worktree = {str(worktree).lower()}\n"
                 if force_ssh:
-                    cfg += f"force_ssh = true\n"
+                    cfg += "force_ssh = true\n"
                 if use_alternate_endpoint:
                     cfg += f'api_url = "http://{ALTERNATE_DOMAIN}:5000/{provider}"\n'
                 cfg += """
@@ -591,7 +590,7 @@ def test_repos_find_remote_user_and_group(
                 if not worktree_default:
                     cfg += f"worktree = {str(worktree).lower()}\n"
                 if force_ssh:
-                    cfg += f"force_ssh = true\n"
+                    cfg += "force_ssh = true\n"
                 if use_alternate_endpoint:
                     cfg += f'api_url = "http://{ALTERNATE_DOMAIN}:5000/{provider}"\n'
                 cfg += """
@@ -742,7 +741,7 @@ def test_repos_find_remote_owner(
                 if not worktree_default:
                     cfg += f"worktree = {str(worktree).lower()}\n"
                 if force_ssh:
-                    cfg += f"force_ssh = true\n"
+                    cfg += "force_ssh = true\n"
                 if use_alternate_endpoint:
                     cfg += f'api_url = "http://{ALTERNATE_DOMAIN}:5000/{provider}"\n'
                 cfg += """
@@ -873,13 +872,11 @@ def test_repos_find_remote_owner(
     assert repo["remotes"][0]["name"] == "origin"
     if force_ssh:
         assert (
-            repo["remotes"][0]["url"] == f"ssh://git@example.com/myuser2/myproject3.git"
+            repo["remotes"][0]["url"] == "ssh://git@example.com/myuser2/myproject3.git"
         )
         assert repo["remotes"][0]["type"] == "ssh"
     else:
-        assert (
-            repo["remotes"][0]["url"] == f"https://example.com/myuser2/myproject3.git"
-        )
+        assert repo["remotes"][0]["url"] == "https://example.com/myuser2/myproject3.git"
         assert repo["remotes"][0]["type"] == "https"
 
     group_namespace_1 = [t for t in output["trees"] if t["root"] == "/myroot/mygroup1"][
@@ -923,13 +920,13 @@ def test_repos_find_remote_owner(
         if force_ssh:
             assert (
                 repo["remotes"][0]["url"]
-                == f"ssh://git@example.com/mygroup1/myproject4.git"
+                == "ssh://git@example.com/mygroup1/myproject4.git"
             )
             assert repo["remotes"][0]["type"] == "ssh"
         else:
             assert (
                 repo["remotes"][0]["url"]
-                == f"https://example.com/mygroup1/myproject4.git"
+                == "https://example.com/mygroup1/myproject4.git"
             )
             assert repo["remotes"][0]["type"] == "https"
 
@@ -948,12 +945,11 @@ def test_repos_find_remote_owner(
     assert repo["remotes"][0]["name"] == "origin"
     if force_ssh:
         assert (
-            repo["remotes"][0]["url"]
-            == f"ssh://git@example.com/mygroup2/myproject5.git"
+            repo["remotes"][0]["url"] == "ssh://git@example.com/mygroup2/myproject5.git"
         )
         assert repo["remotes"][0]["type"] == "ssh"
     else:
         assert (
-            repo["remotes"][0]["url"] == f"https://example.com/mygroup2/myproject5.git"
+            repo["remotes"][0]["url"] == "https://example.com/mygroup2/myproject5.git"
         )
         assert repo["remotes"][0]["type"] == "https"
diff --git a/e2e_tests/test_repos_status.py b/e2e_tests/test_repos_status.py
index 8787dea..e9a7511 100644
--- a/e2e_tests/test_repos_status.py
+++ b/e2e_tests/test_repos_status.py
@@ -1,8 +1,6 @@
 #!/usr/bin/env python3
 
-import tempfile
-
-from helpers import *
+from helpers import RepoTree, grm
 
 
 def test_repos_sync_worktree_clone():
diff --git a/e2e_tests/test_repos_sync.py b/e2e_tests/test_repos_sync.py
index bba5b7c..8833aee 100644
--- a/e2e_tests/test_repos_sync.py
+++ b/e2e_tests/test_repos_sync.py
@@ -1,14 +1,21 @@
 #!/usr/bin/env python3
 
-import tempfile
+import os
 import re
+import subprocess
+import tempfile
 import textwrap
 
-import pytest
-import toml
 import git
-
-from helpers import *
+import pytest
+from helpers import (
+    NonExistentPath,
+    TempGitFileRemote,
+    TempGitRepository,
+    checksum_directory,
+    grm,
+    shell,
+)
 
 templates = {
     "repo_simple": {
@@ -291,7 +298,9 @@ def test_repos_sync_unmanaged_repos(configtype):
                 # this removes the prefix (root) from the path (unmanaged_repo)
                 unmanaged_repo_name = os.path.relpath(unmanaged_repo, root)
                 regex = f".*unmanaged.*{unmanaged_repo_name}"
-                assert any([re.match(regex, l) for l in cmd.stderr.lower().split("\n")])
+                assert any(
+                    [re.match(regex, line) for line in cmd.stderr.lower().split("\n")]
+                )
 
 
 @pytest.mark.parametrize("configtype", ["toml", "yaml"])
@@ -374,7 +383,7 @@ def test_repos_sync_repo_in_subdirectory(configtype):
                     assert urls[0] == f"file://{remote}"
 
                 cmd = grm(["repos", "sync", "config", "--config", config.name])
-                assert not "found unmanaged repository" in cmd.stderr.lower()
+                assert "found unmanaged repository" not in cmd.stderr.lower()
 
 
 @pytest.mark.parametrize("configtype", ["toml", "yaml"])
@@ -419,7 +428,7 @@ def test_repos_sync_nested_clone(configtype):
                     cmd = grm(["repos", "sync", "config", "--config", config.name])
                     print(cmd.stdout)
                     print(cmd.stderr)
-                    assert not "found unmanaged repository" in cmd.stderr.lower()
+                    assert "found unmanaged repository" not in cmd.stderr.lower()
 
 
 @pytest.mark.parametrize("configtype", ["toml", "yaml"])
@@ -720,14 +729,14 @@ def test_repos_sync_invalid_syntax(configtype):
         with open(config.name, "w") as f:
             if configtype == "toml":
                 f.write(
-                    f"""
+                    """
                     [[trees]]
                     root = invalid as there are no quotes ;)
                 """
                 )
             elif configtype == "yaml":
                 f.write(
-                    f"""
+                    """
                     trees:
                     wrong:
                     indentation:
@@ -779,8 +788,6 @@ def test_repos_sync_normal_change_to_worktree(configtype):
                     cmd = grm(["repos", "sync", "config", "--config", config.name])
                     assert cmd.returncode == 0
 
-                    git_dir = os.path.join(target, "test")
-
                     with open(config.name, "w") as f:
                         f.write(
                             templates["worktree_repo_with_remote"][configtype].format(
@@ -810,8 +817,6 @@ def test_repos_sync_worktree_change_to_normal(configtype):
                     cmd = grm(["repos", "sync", "config", "--config", config.name])
                     assert cmd.returncode == 0
 
-                    git_dir = os.path.join(target, "test")
-
                     with open(config.name, "w") as f:
                         f.write(
                             templates["repo_with_remote"][configtype].format(
diff --git a/e2e_tests/test_worktree_clean.py b/e2e_tests/test_worktree_clean.py
index b64172a..cc1958a 100644
--- a/e2e_tests/test_worktree_clean.py
+++ b/e2e_tests/test_worktree_clean.py
@@ -1,8 +1,17 @@
 #!/usr/bin/env python3
 
-import pytest
+import os
 
-from helpers import *
+import pytest
+from helpers import (
+    NonGitDir,
+    TempGitRepository,
+    TempGitRepositoryWorktree,
+    checksum_directory,
+    funcname,
+    grm,
+    shell,
+)
 
 
 def test_worktree_clean():
@@ -153,13 +162,13 @@ def test_worktree_clean_configured_default_branch(
             with open(os.path.join(base_dir, "grm.toml"), "w") as f:
                 if branch_list_empty:
                     f.write(
-                        f"""
+                        """
                         persistent_branches = []
                     """
                     )
                 else:
                     f.write(
-                        f"""
+                        """
                         persistent_branches = [
                             "mybranch"
                         ]
diff --git a/e2e_tests/test_worktree_config_presistent_branch.py b/e2e_tests/test_worktree_config_presistent_branch.py
index e7d2923..cae4c57 100644
--- a/e2e_tests/test_worktree_config_presistent_branch.py
+++ b/e2e_tests/test_worktree_config_presistent_branch.py
@@ -2,7 +2,8 @@
 
 import os.path
 
-from helpers import *
+import git
+from helpers import TempGitRepositoryWorktree, checksum_directory, funcname, grm, shell
 
 
 def test_worktree_never_clean_persistent_branches():
diff --git a/e2e_tests/test_worktree_conversion.py b/e2e_tests/test_worktree_conversion.py
index 7f1448d..b06b32a 100644
--- a/e2e_tests/test_worktree_conversion.py
+++ b/e2e_tests/test_worktree_conversion.py
@@ -1,8 +1,16 @@
 #!/usr/bin/env python3
 
-import tempfile
+import os
 
-from helpers import *
+from helpers import (
+    EmptyDir,
+    NonGitDir,
+    TempGitRepository,
+    TempGitRepositoryWorktree,
+    checksum_directory,
+    funcname,
+    grm,
+)
 
 
 def test_convert():
diff --git a/e2e_tests/test_worktree_fetch.py b/e2e_tests/test_worktree_fetch.py
index a30ef7d..232948b 100644
--- a/e2e_tests/test_worktree_fetch.py
+++ b/e2e_tests/test_worktree_fetch.py
@@ -1,11 +1,17 @@
 #!/usr/bin/env python3
 
-from helpers import *
-
 import re
 
-import pytest
 import git
+import pytest
+from helpers import (
+    EmptyDir,
+    TempGitFileRemote,
+    TempGitRepositoryWorktree,
+    funcname,
+    grm,
+    shell,
+)
 
 
 def test_worktree_fetch():
diff --git a/e2e_tests/test_worktree_rebase.py b/e2e_tests/test_worktree_rebase.py
index 0c73c79..6f18fe3 100644
--- a/e2e_tests/test_worktree_rebase.py
+++ b/e2e_tests/test_worktree_rebase.py
@@ -1,11 +1,11 @@
 #!/usr/bin/env python3
 
-from helpers import *
-
+import os
 import re
 
-import pytest
 import git
+import pytest
+from helpers import TempGitRepositoryWorktree, funcname, grm, shell
 
 
 @pytest.mark.parametrize("pull", [True, False])
diff --git a/e2e_tests/test_worktree_status.py b/e2e_tests/test_worktree_status.py
index d54788f..39eccc6 100644
--- a/e2e_tests/test_worktree_status.py
+++ b/e2e_tests/test_worktree_status.py
@@ -1,10 +1,17 @@
 #!/usr/bin/env python3
 
+import os
 import re
 
-from helpers import *
-
 import pytest
+from helpers import (
+    NonGitDir,
+    TempGitRepository,
+    TempGitRepositoryWorktree,
+    funcname,
+    grm,
+    shell,
+)
 
 
 @pytest.mark.parametrize("has_config", [True, False])
diff --git a/e2e_tests/test_worktrees.py b/e2e_tests/test_worktrees.py
index e5b9b48..8f90580 100644
--- a/e2e_tests/test_worktrees.py
+++ b/e2e_tests/test_worktrees.py
@@ -1,12 +1,18 @@
 #!/usr/bin/env python3
 
-from helpers import *
+import datetime
+import os.path
 
 import git
 import pytest
-import datetime
-
-import os.path
+from helpers import (
+    TempGitRepositoryWorktree,
+    checksum_directory,
+    funcname,
+    grm,
+    shell,
+    tempfile,
+)
 
 
 @pytest.mark.parametrize(
@@ -151,18 +157,20 @@ def test_worktree_add(
             ]
         )
 
-    cachefn = lambda nr: "_".join(
-        [
-            str(nr),
-            str(default_remote),
-            str(local_branch_exists),
-            str(remote_branch_already_exists),
-            str(remote_branch_with_prefix_already_exists),
-            str(remote_count),
-            str(remotes_differ),
-            str(worktree_name),
-        ]
-    )
+    def cachefn(nr):
+        return "_".join(
+            [
+                str(nr),
+                str(default_remote),
+                str(local_branch_exists),
+                str(remote_branch_already_exists),
+                str(remote_branch_with_prefix_already_exists),
+                str(remote_count),
+                str(remotes_differ),
+                str(worktree_name),
+            ]
+        )
+
     remote1_cache_key = cachefn(1)
     remote2_cache_key = cachefn(2)
 
@@ -281,7 +289,7 @@ def test_worktree_add(
                 and remotes_differ
             ):
                 assert (
-                    f"branch exists on multiple remotes, but they deviate"
+                    "branch exists on multiple remotes, but they deviate"
                     in cmd.stderr.lower()
                 )
                 assert len(cmd.stderr.strip().split("\n")) == base + 1
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 0000000..124501d
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,3 @@
+[toolchain]
+channel = "nightly"
+targets = ["x86_64-unknown-linux-musl"]
diff --git a/src/grm/cmd.rs b/src/grm/cmd.rs
index 4b0fd1e..d269610 100644
--- a/src/grm/cmd.rs
+++ b/src/grm/cmd.rs
@@ -63,6 +63,14 @@ pub struct FindLocalArgs {
     #[clap(help = "The path to search through")]
     pub path: String,
 
+    #[clap(
+        short,
+        long,
+        help = "Exclude repositories that match the given regex",
+        name = "REGEX"
+    )]
+    pub exclude: Option<String>,
+
     #[clap(
         value_enum,
         short,
diff --git a/src/grm/main.rs b/src/grm/main.rs
index aa522b4..3d02872 100644
--- a/src/grm/main.rs
+++ b/src/grm/main.rs
@@ -199,7 +199,8 @@ fn main() {
                         }
                     };
 
-                    let (found_repos, warnings) = match find_in_tree(&path) {
+                    let (found_repos, warnings) = match find_in_tree(&path, args.exclude.as_deref())
+                    {
                         Ok((repos, warnings)) => (repos, warnings),
                         Err(error) => {
                             print_error(&error);
diff --git a/src/lib.rs b/src/lib.rs
index cdfc596..9304675 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -19,12 +19,22 @@ pub mod worktree;
 /// The bool in the return value specifies whether there is a repository
 /// in root itself.
 #[allow(clippy::type_complexity)]
-fn find_repos(root: &Path) -> Result<Option<(Vec<repo::Repo>, Vec<String>, bool)>, String> {
+fn find_repos(
+    root: &Path,
+    exclusion_pattern: Option<&str>,
+) -> Result<Option<(Vec<repo::Repo>, Vec<String>, bool)>, String> {
     let mut repos: Vec<repo::Repo> = Vec::new();
     let mut repo_in_root = false;
     let mut warnings = Vec::new();
 
+    let exlusion_regex: regex::Regex = regex::Regex::new(exclusion_pattern.unwrap_or(r"^$"))
+        .map_err(|e| format!("invalid regex: {e}"))?;
     for path in tree::find_repo_paths(root)? {
+        if exclusion_pattern.is_some() && exlusion_regex.is_match(&path::path_as_string(&path)) {
+            warnings.push(format!("[skipped] {}", &path::path_as_string(&path)));
+            continue;
+        }
+
         let is_worktree = repo::RepoHandle::detect_worktree(&path);
         if path == root {
             repo_in_root = true;
@@ -130,10 +140,14 @@ fn find_repos(root: &Path) -> Result<Option<(Vec<repo::Repo>, Vec<String>, bool)
     Ok(Some((repos, warnings, repo_in_root)))
 }
 
-pub fn find_in_tree(path: &Path) -> Result<(tree::Tree, Vec<String>), String> {
+pub fn find_in_tree(
+    path: &Path,
+    exclusion_pattern: Option<&str>,
+) -> Result<(tree::Tree, Vec<String>), String> {
     let mut warnings = Vec::new();
 
-    let (repos, repo_in_root): (Vec<repo::Repo>, bool) = match find_repos(path)? {
+    let (repos, repo_in_root): (Vec<repo::Repo>, bool) = match find_repos(path, exclusion_pattern)?
+    {
         Some((vec, mut repo_warnings, repo_in_root)) => {
             warnings.append(&mut repo_warnings);
             (vec, repo_in_root)