diff --git a/dedup.lua b/dedup.lua
index bbd4968..979da18 100644
--- a/dedup.lua
+++ b/dedup.lua
@@ -23,7 +23,7 @@ allowed_dups = confgetlist("RPM::Allow-Duplicated")
 function isAllowed(pkg)
     for i, pattern in pairs(allowed_dups) do
 	-- ugly hack: lua is bad at pattern matching
-	if os.execute("echo '"..pkg.."' |egrep -q '"..pattern.."'") then
+	if os.execute("echo '"..pkg.."' |grep -E -q '"..pattern.."'") then
 	    return 1
 	end
     end
@@ -73,4 +73,3 @@ for i, pkg in pairs(pkglist()) do
 
     ::continue::
 end
-