diff --git a/autoload/ack.vim b/autoload/ack.vim
index b6afdba4..fe9cc8ac 100644
--- a/autoload/ack.vim
+++ b/autoload/ack.vim
@@ -26,7 +26,7 @@ function! ack#Ack(cmd, args) "{{{
   " Strip some options that are meaningless for path search and set match
   " format accordingly.
   if s:SearchingFilepaths()
-    let l:grepprg = substitute(l:grepprg, '-H\|--column', '', 'g')
+    let l:grepprg = substitute(l:grepprg, '-H\|--column\C', '', 'g')
     let l:grepformat = '%f'
   endif