diff --git a/lib/grep.zsh b/lib/grep.zsh
index 276fec382..7cc20952e 100644
--- a/lib/grep.zsh
+++ b/lib/grep.zsh
@@ -6,19 +6,21 @@
 GREP_OPTIONS="--color=auto"
 
 # avoid VCS folders (if the necessary grep flags are available)
+VCS_folders="{.bzr,.cvs,.git,.hg,.svn}"
+
 grep-flag-available() {
-    echo | grep $1 "" >/dev/null 2>&1
+    echo | command grep $1 "" >/dev/null 2>&1
 }
 if grep-flag-available --exclude-dir=.cvs; then
-    for PATTERN in .cvs .git .hg .svn; do
-        GREP_OPTIONS+=" --exclude-dir=$PATTERN"
-    done
+    GREP_OPTIONS+=" --exclude-dir=$VCS_folders"
 elif grep-flag-available --exclude=.cvs; then
-    for PATTERN in .cvs .git .hg .svn; do
-        GREP_OPTIONS+=" --exclude=$PATTERN"
-    done
+    GREP_OPTIONS+=" --exclude=$VCS_folders"
 fi
-unfunction grep-flag-available
 
 export GREP_OPTIONS="$GREP_OPTIONS"
 export GREP_COLOR='1;32'
+
+
+# cleanup
+unset VCS_folders
+unfunction grep-flag-available