diff --git a/shell/hush_leaktool.sh b/shell/hush_leaktool.sh
index 54a19aa..54161b3 100644
--- a/shell/hush_leaktool.sh
+++ b/shell/hush_leaktool.sh
@@ -8,6 +8,6 @@
 grep -v free "$output" >temp1
 for freed in $freelist; do
     echo Dropping $freed
-    cat temp1 | grep -v $freed >temp2
+    grep -v $freed <temp1 >temp2
     mv temp2 temp1
 done