diff --git a/pre-commit.d/20warn-problem-files b/pre-commit.d/20warn-problem-files
index 43320e4..7899268 100755
--- a/pre-commit.d/20warn-problem-files
+++ b/pre-commit.d/20warn-problem-files
@@ -1,19 +1,20 @@
 #!/bin/sh
 set -e
 
-exclude_internal () {
-	grep -E -v '(^|/)(\.git|\.hg|\.bzr|_darcs)/'
-}
+# (Note that when using this, the find expression must end with
+# -print or -exec, else the excluded directories will actually be
+# printed!)
+NOVCS='. -path ./.git -prune -o -path ./.bzr -prune -o -path ./.hg -prune -o -path ./_darcs -prune -o'
 
 if [ "$VCS" = bzr ] || [ "$VCS" = darcs ]; then
-	special=$(find . ! -type d ! -type f ! -type l | exclude_internal) || true
-	hardlinks=$(find . -type f ! -links 1 | exclude_internal ) || true
+	special=$(find $NOVCS ! -type d ! -type f ! -type l -print) || true
+	hardlinks=$(find $NOVCS -type f ! -links 1 -print) || true
 elif [ "$VCS" = hg ]; then
-	special=$(find . ! -type d ! -type f ! -type l | exclude_internal) || true
-	hardlinks=$(find . -type f ! -links 1 -exec hg status {} \; | exclude_internal ) || true
+	special=$(find $NOVCS ! -type d ! -type f ! -type l -print) || true
+	hardlinks=$(find $NOVCS -type f ! -links 1 -exec hg status {} \; -print) || true
 elif [ "$VCS" = git ]; then
-	special=$(find . ! -type d ! -type f ! -type l -exec git ls-files --exclude-standard --cached --others {} + | exclude_internal) || true
-	hardlinks=$(find . -type f ! -links 1 -exec git ls-files --exclude-standard --cached --others {} + | exclude_internal) || true
+	special=$(find $NOVCS ! -type d ! -type f ! -type l -exec git ls-files --exclude-standard --cached --others {} + -print) || true
+	hardlinks=$(find $NOVCS -type f ! -links 1 -exec git ls-files --exclude-standard --cached --others {} + -print) || true
 else
 	special=""
 fi