diff --git a/listings/chap2/hello_proper_exit/hello_proper_exit.asm b/listings/chap2/hello_proper_exit/hello_proper_exit.asm
index d9923e0..4692e7f 100755
--- a/listings/chap2/hello_proper_exit/hello_proper_exit.asm
+++ b/listings/chap2/hello_proper_exit/hello_proper_exit.asm
@@ -11,7 +11,7 @@ _start:
     mov     rdx, 14          ; string length in bytes
     syscall
 
-	mov     rax, 60          ; 'exit' syscall number
+    mov     rax, 60          ; 'exit' syscall number
     xor     rdi, rdi
     syscall