diff --git a/copy.sh b/copy.sh
index 5505217..bc21e94 100755
--- a/copy.sh
+++ b/copy.sh
@@ -38,9 +38,16 @@ echo "$dotfiles" | while read -r dotfile; do
 done
 
 function add-export {
-  if ! grep "$1" "$HOME/.zsh_local" &> /dev/null; then
-    echo "$1\"$2\"" >> "$HOME/.zsh_local"
+  local final="$1\"$2\""
+  if grep "$final" "$HOME/.zsh_local" &> /dev/null; then
+    return
   fi
+  if grep "$1" "$HOME/.zsh_local" &> /dev/null; then
+    echo "Replacing '$(grep "$1" "$HOME/.zsh_local")' with '$final'"
+    local escaped="$(echo "$1" | sed 's@/@\\/@g')"
+    sed -i "/$escaped/d" "$HOME/.zsh_local"
+  fi
+  echo "$final" >> "$HOME/.zsh_local"
 }
 
 add-export "export DOT_DIR=" "$SCRIPT_DIR"