diff --git a/ynh-dev b/ynh-dev
index 1dadcd4..57a2f69 100755
--- a/ynh-dev
+++ b/ynh-dev
@@ -175,12 +175,12 @@ elif [ "$1" = "run" ]; then
         }
 
         # Adapt vagrantfile
-        sed -i "/  ### END AUTOMATIC YNH-DEV ###/ i \\
-  config.vm.define \"${VMNAME}\" do |${VMNAME}| \
+        perl -i -pe "s|  (### END AUTOMATIC YNH-DEV ###)|\
+  config.vm.define \"${VMNAME}\" do \|${VMNAME}\| \
 \n    ${VMNAME}.vm.box = \"${BOX_NAME}\" \
 \n    ${VMNAME}.vm.network :private_network, ip: \"${IP}\" \
 \n  end \
-\n" ./Vagrantfile
+\n  \1|" ./Vagrantfile
     }
 
     # Run VM