Postfix aliases why can't I amend them?

I have a new user to add to my postfix aliases, a file which passed through the ML upgrade process and is working OK for existing users. The new user is picking up direct mail, but i need to add him into an existing alias group for "info" @mydomain. I found and opened my previous file /etc/aliases, added the new user, ran sudo new aliases, (also ran sudo postfix reload for good measure). However I get a "fatal: open /etc/aliases: No such file or directory" error.

I have checked text in Main.cf file and aliases resolves to my /etc/ folder.

Can anyone help?