diff --git a/pyproject.toml b/pyproject.toml
index 31c1ed5..64bf540 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "rapidchecker"
-version = "0.1.3"
+version = "0.1.4"
 description = " Grammar and format checker for ABB RAPID code. "
 readme = "README.md"
 requires-python = ">=3.10"
diff --git a/rapidchecker/cli.py b/rapidchecker/cli.py
index 0ddb82b..a232617 100644
--- a/rapidchecker/cli.py
+++ b/rapidchecker/cli.py
@@ -1,5 +1,4 @@
 import sys
-from pathlib import Path
 
 import click
 from pyparsing import ParseBaseException
@@ -8,14 +7,10 @@
 from rapidchecker.whitespace_checks import WhiteSpaceError
 
 from .check import check_format
+from .io import get_sys_files, read_sys_file
 from .whitespace_checks import check_whitespace
 
 
-def read_sys_file(path: str | Path) -> str:
-    with Path(path).open() as f:
-        return f.read()
-
-
 def check_file(file_contents: str) -> list[ParseBaseException | WhiteSpaceError]:
     errors: list[ParseBaseException | WhiteSpaceError] = []
     errors.extend(check_format(file_contents))
@@ -25,11 +20,11 @@ def check_file(file_contents: str) -> list[ParseBaseException | WhiteSpaceError]
 
 
 @click.command()
-@click.argument("paths", nargs=-1, type=click.Path(exists=True, dir_okay=False))
+@click.argument("paths", nargs=-1, type=click.Path(exists=True, dir_okay=True))
 def cli(paths: list[str]) -> None:
     found_errors = False
 
-    for filepath in paths:
+    for filepath in get_sys_files(paths):
         errors = check_file(read_sys_file(filepath))
         if not errors:
             continue
diff --git a/rapidchecker/io.py b/rapidchecker/io.py
new file mode 100644
index 0000000..d019140
--- /dev/null
+++ b/rapidchecker/io.py
@@ -0,0 +1,16 @@
+from collections.abc import Iterable
+from pathlib import Path
+
+
+def get_sys_files(paths: list[str]) -> Iterable[Path]:
+    for path_str in paths:
+        path = Path(path_str)
+        if path.is_dir():
+            yield from path.glob("**/*.sys")
+        else:
+            yield path
+
+
+def read_sys_file(path: str | Path) -> str:
+    with Path(path).open() as f:
+        return f.read()
diff --git a/uv.lock b/uv.lock
index 22e8238..c4bab31 100644
--- a/uv.lock
+++ b/uv.lock
@@ -286,7 +286,7 @@ wheels = [
 
 [[package]]
 name = "rapidchecker"
-version = "0.1.3"
+version = "0.1.4"
 source = { virtual = "." }
 dependencies = [
     { name = "click" },