diff --git a/init/11_new_user.sh b/init/11_new_user.sh
index b5ac305..9d0cf40 100644
--- a/init/11_new_user.sh
+++ b/init/11_new_user.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 
-if [ "$(id -u abc)" != "$PUID" ]; then usermod -o -u "$PUID" abc ; fi
-if [ "$(id -g abc)" != "$PGID" ]; then groupmod -o -g  "$PGID" abc ; fi
+if [ -n "$PUID" -a "$(id -u abc)" != "$PUID" ]; then usermod -o -u "$PUID" abc ; fi
+if [ -n "$PGID" -a "$(id -g abc)" != "$PGID" ]; then groupmod -o -g  "$PGID" abc ; fi
 
 echo "
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