diff --git a/docs/_docs/vagrant.md b/docs/_docs/vagrant.md
index 244cd4ba7..0239366b9 100644
--- a/docs/_docs/vagrant.md
+++ b/docs/_docs/vagrant.md
@@ -42,7 +42,7 @@ vagrant up ubuntu-xenial --provider=libvirt
 
 ```bash
 sudo apt install vagrant vagrant-libvirt libvirt-daemon-system vagrant-mutate libvirt-dev
-sudo usermod -a -G libvirt $USER
+sudo usermod -aG libvirt $USER
 
 # Reboot