diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..13fdb04
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,18 @@
+use anyhow::Result;
+
+pub fn find_matches(content: &str, pattern: &str, mut writer: impl std::io::Write) -> Result<()> {
+    for line in content.lines() {
+        if line.contains(pattern) {
+            writeln!(writer, "{}", line)?;
+        }
+    }
+    Ok(())
+}
+
+#[test]
+fn find_a_match() -> Result<(), Box<dyn std::error::Error>> {
+    let mut result = Vec::new();
+    find_matches("lorem ipsum\ndolar sit amet", "lorem", &mut result)?;
+    assert_eq!(result, b"lorem ipsum\n");
+    Ok(())
+}
diff --git a/src/main.rs b/src/main.rs
index 1c67f06..1bf8715 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -14,12 +14,10 @@ fn main() -> Result<()> {
     info!("starting up");
     let args = Cli::parse();
 
-    // let content = std::fs::read_to_string(&args.path).expect("Could not read file.");
-
     let content = std::fs::read_to_string(&args.path)
         .with_context(|| format!("could not read file `{}`.", args.path.display()))?;
 
-    find_matches(
+    grrs::find_matches(
         content.as_str(),
         args.pattern.as_str(),
         &mut std::io::stdout(),
@@ -28,23 +26,6 @@ fn main() -> Result<()> {
     Ok(())
 }
 
-fn find_matches(content: &str, pattern: &str, mut writer: impl std::io::Write) -> Result<()> {
-    for line in content.lines() {
-        if line.contains(pattern) {
-            writeln!(writer, "{}", line)?;
-        }
-    }
-    Ok(())
-}
-
-#[test]
-fn find_a_match() -> Result<(), Box<dyn std::error::Error>> {
-    let mut result = Vec::new();
-    find_matches("lorem ipsum\ndolar sit amet", "lorem", &mut result)?;
-    assert_eq!(result, b"lorem ipsum\n");
-    Ok(())
-}
-
 #[allow(dead_code)]
 fn answer() -> i32 {
     return 42;