diff --git a/go.mod b/go.mod
index d3f4e74..155a502 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
-module github.com/thzoid/brainfuck
+module github.com/thzoid/brainf
 
 go 1.18
diff --git a/main.go b/main.go
index a50096e..19d5f53 100644
--- a/main.go
+++ b/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"path/filepath"
 )
 
 var memory = []byte{0}
@@ -56,9 +57,17 @@ func runOp(i int, c byte) int {
 
 func main() {
 	p, err := os.ReadFile(os.Args[1])
+
+	ext := filepath.Ext(os.Args[1])
+
 	if err != nil {
 		panic(err)
 	}
+
+	if ext != ".bf" {
+		panic("provided script must be a .bf file")
+	}
+
 	program = p
 
 	for i := 0; i < len(program); i++ {