FQDN SSH login function
I don’t use unqualified hostnames for ssh logins. They’re too dependent on local context. The command ssh myhost leaves it up to the local DNS resolver to append a domain name to myhost, and too often the local DNS resolver is influenced by a DHCP server of unknown provenance.
On the other hand, laziness dictates that I reduce the amount of typing I do to login, so the command ssh myhost.mysubdomain.mydomain isn’t a winner for me either.
The solution is a domain-specific login function I’ve added to my .bash_profile shell initialization file:
function mli {
ssh ${2:+"${2}@"}${1:?"usage: $FUNCNAME host [user]"}.madboa.com
}
Notes:
- The general usage is
mli host [user]. The host parameter gets prepended to my domain (madboa.com). If there’s a user parameter, it gets prepended to the host’s FQDN with an@character between the username and hostname. mlistands for “madboa login”; I have functions with similar three-letter names for other domains.${2:+"${2}@"}means “if there’s a second parameter passed to this function, expand it to “parameter@”; it’s an optional username.${1:?"usage: $FUNCNAME host [user]"}means “expand the first parameter passed to this function here; if there is no parameter, exit function with the error message found after the question mark.”
Logging into my web server is as simple as
# this expands to "ssh www.madboa.com"
mli www
If I want to login as root, I just add a user parameter:
# this expands to "ssh root@www.madboa.com"
mli www root
Getting a usage message is as simple as invoking the function without any parameters.
[~]$ mli
-bash: 1: usage: mli host [user]