update 'passwd' advice

Author: snori74

1.md

@@ -58,7 +58,7 @@ Try these simple commands:
 	df -h      	 
 	uname -a   
 
-Now use the *passwd* command to change your password. To do this, think of a new, secure password, then simply type *passwd*, press “Enter” and give your current password when prompted, then the new one you've chosen, confirm it  - and then WRITE IT DOWN somewhere.
+If you're using a password to login (rather than public key), then now is a good time to ensure that this is very strong and unique - i.e. At least 10 characters - because your server is fully exposed to bots that will be continuosly attempting to break in. Use the *passwd* command to change your password. To do this, think of a new, secure password, then simply type *passwd*, press “Enter” and give your current password when prompted, then the new one you've chosen, confirm it  - and then WRITE IT DOWN somewhere. In a production system of course, public keys and/or two factor authentication would be more appropriate.
 
 It's very handy to be able to cut and paste text between your remote session and your local desktop, so spend some time getting confident with how to do this in your setup.