Last year, a blog entry by Joël “from the Internet” caught my attention on HN. He wrote about the benefits of using an SSH configuration file to avoid typing full host names, user login names and deviating SSH ports and reduce the work to make a port forwarded connection. Because it simplified my life as advertised, I strongly urge you to read the blog post right now!
Things get even more efficient, if you have a large array of machines with host
names that follow a certain pattern. In my case, I have access to a cluster of
GPU and CPU nodes, all bearing the same prefix and a per-machine number. Instead
of repeating myself over and over again, I can specify a wild carded pattern
that matches zero or more (
*) characters or exactly one (
Host foo-*-?.bar.baz.co.uk User me IdentityFile ~/.ssh/foo_key
Still, it is tiresome to type the fully qualified host name. But it can be
shortened (provided that OpenSSH>=5.6 is installed) by re-using the expanded
nickname with the
Host foo-*-? User me HostName %h.bar.baz.co.uk IdentityFile ~/.ssh/foo_key
Now, I can simply log into a machine with
ssh foo-gpu-1 instead of
~/.ssh/foo_key email@example.com. The manpage on
ssh_config is a
nice and short read, so don’t miss out the other available options.
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