Editing /etc/hosts on Mac OS X Lion to use shorter host for ssh-ing

Question

I keep having to type out ssh myusername@somereallylonghost.numb3r5.ojd202nk.net a lot. Instead of an alias, I just want to shorten that host name. I tried editing my hosts file to include shorthost somereallylonghost.numb3r5.ojd202nk.net at the bottom, but it's not resolving when I try to connect as ssh myusername@shorthost. Can anyone tell me why?

Answer 1

Use the ssh config file instead. The file path is ~/.ssh/config.

Example config:

Host shorthost
  User myusername
  HostName somereallylonghost.numb3r5.ojd202nk.net

Then you can just run ssh shorthost.

Answer 2

Please accept @ggustafsson's solution. But since you asked why /etc/hosts didn't work, and he didn't cover that, I thought I'd cover it:

/etc/hosts is for mapping one or more hostnames to an IP address. It's not for mapping one name to another. Because it's not designed to do what you're looking for, it doesn't provide syntax for doing what you want. The syntax you made up is meaningless/invalid to the process that reads /etc/hosts, which expects each line to start with a numeric IP address.

Answer 3

If your only concern is ssh, you should accept ggustafsson's answer. However, if you need that for other IP tasks as well (e.g. ftp, ping, ...), and the host in question has a fixed ip (say, 123.123.123.123 to have an example), you could add a line to your /etc/hosts like this:

123.123.123.123 shorthost

(optionally, you could also add your somereallylonghost at the end of that, so that would also be resolved regardless of some DNS server being available). But keep in mind you'd have to update that line whenever the IP of your verylonghostnametoreplaceinthiscase changes -- which is not the case with the ssh config approach.