Update docs/guide.md

Co-authored-by: Ben Potter <[email protected]>

Author: jsjoeio

docs/guide.md

@@ -381,9 +381,9 @@ Follow these steps where code-server is running:
 1. Install `openssh-server`, `wget`, and `unzip`. 
 
 ```bash
+# example for Debian and Ubuntu operating systems
 sudo apt update
 sudo apt install wget unzip openssh-server
-```
 
 2.  Start OpenSSH-Server and set the password of your computer. Eg. If you use a Railway deployment, the user is `coder` and so, the command to change the password would be `sudo passwd coder`.