diff --git a/Cargo.lock b/Cargo.lock
index 105f303..a53ea94 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b2969dcb958b36655471fc61f7e416fa76033bdd4bfed0678d8fee1e2d07a1f0"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "anstream"
 version = "0.6.11"
@@ -50,6 +59,16 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "bstr"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c48f0051a4b4c5e0b6d365cd04af53aeaa209e3cc15ec2cdb69e73cc87fbd0dc"
+dependencies = [
+ "memchr",
+ "serde",
+]
+
 [[package]]
 name = "clap"
 version = "4.5.0"
@@ -96,12 +115,78 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "acbf1af155f9b9ef647e42cdc158db4b64a1b61f743629225fde6f3e0be2a7c7"
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+dependencies = [
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "248e3bacc7dc6baa3b21e405ee045c3047101a49145e7e9eca583ab4c2ca5345"
+
+[[package]]
+name = "globset"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57da3b9b5b85bd66f31093f8c408b90a74431672542466497dcbdfdc02034be1"
+dependencies = [
+ "aho-corasick",
+ "bstr",
+ "log",
+ "regex-automata",
+ "regex-syntax",
+]
+
 [[package]]
 name = "heck"
 version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
 
+[[package]]
+name = "ignore"
+version = "0.4.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b46810df39e66e925525d6e38ce1e7f6e1d208f72dc39757880fcb66e2c58af1"
+dependencies = [
+ "crossbeam-deque",
+ "globset",
+ "log",
+ "memchr",
+ "regex-automata",
+ "same-file",
+ "walkdir",
+ "winapi-util",
+]
+
+[[package]]
+name = "log"
+version = "0.4.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5e6163cb8c49088c2c36f57875e58ccd8c87c7427f7fbd50ea6710b2f3f2e8f"
+
+[[package]]
+name = "memchr"
+version = "2.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "523dc4f511e55ab87b694dc30d0f820d60906ef06413f93d4d7a1385599cc149"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.78"
@@ -120,11 +205,58 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "regex-automata"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5bb987efffd3c6d0d8f5f89510bb458559eab11e4f869acb20bf845e016259cd"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c08c74e62047bb2de4ff487b251e4a92e24f48745648451635cec7d591162d9f"
+
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "saul"
 version = "0.1.0"
 dependencies = [
  "clap",
+ "ignore",
+]
+
+[[package]]
+name = "serde"
+version = "1.0.196"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "870026e60fa08c69f064aa766c10f10b1d62db9ccd4d0abb206472bee0ce3b32"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.196"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33c85360c95e7d137454dc81d9a4ed2b8efd8fbe19cee57357b32b9771fccb67"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -156,6 +288,47 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a"
 
+[[package]]
+name = "walkdir"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d71d857dc86794ca4c280d616f7da00d2dbfd8cd788846559a6813e6aa4b54ee"
+dependencies = [
+ "same-file",
+ "winapi-util",
+]
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-util"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f29e6f9198ba0d26b4c9f07dbe6f9ed633e1f3d5b8b414090084349e46a52596"
+dependencies = [
+ "winapi",
+]
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-sys"
 version = "0.52.0"
diff --git a/Cargo.toml b/Cargo.toml
index fc8152b..eb70491 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,3 +8,4 @@ license = "AGPL-3.0-or-later"
 
 [dependencies]
 clap = { version = "4.5.0", features = ["derive"] }
+ignore = "0.4.22"
diff --git a/src/main.rs b/src/main.rs
index 344ba26..8c67afd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,24 +19,48 @@
 use std::{fs::File, io::BufReader, path::PathBuf};
 
 use clap::Parser;
+use ignore::Walk;
 
 mod parse;
 
 #[derive(Debug, Parser)]
 struct Args {
-    /// A list of files to validate.
+    /// A list of paths to validate.
     pub input: Vec<PathBuf>,
 }
 
 fn main() {
-    let args = Args::parse();
+    let mut args = Args::parse();
+
+    if args.input.is_empty() {
+        args.input = vec![".".into()];
+    }
 
     for input in args.input {
-        let f = File::open(&input).unwrap();
-        let mut read = BufReader::new(f);
-        let lines = parse::Language::RUST.read_header(&mut read).unwrap();
-        let header = parse::Header::parse(lines).unwrap();
+        for result in Walk::new(&input) {
+            let entry = match result {
+                Ok(entry) => entry,
+                Err(err) => {
+                    eprintln!("error: {}", err);
+                    continue;
+                }
+            };
 
-        println!("{:?}: {:#?}", input, header);
+            let Some(ft) = entry.file_type() else {
+                continue;
+            };
+
+            if !ft.is_file() {
+                continue;
+            }
+
+            let path = entry.path();
+            let f = File::open(path).unwrap();
+            let mut read = BufReader::new(f);
+            let lines = parse::Language::RUST.read_header(&mut read).unwrap();
+            let header = parse::Header::parse(lines).unwrap();
+
+            println!("{:?}: {:#?}", path, header);
+        }
     }
 }