Speed Up Your Remote Life

ssh -p 2022 -l rob -i ~/.ssh/identity_work_rsa work-server.com

SSH'ing to servers can get a little cumbersome, especially when you're working with a lot of remote systems and multiple identity files.

Luckily, we have a brilliant tool to help us out. Its called ~/.ssh/config, this great little file can speed up our SSH'ing five fold!

Lets make a start.

First lets actually create our file, touch ~/.ssh/config - be sure to execute this as you i.e. not root

As our first example, we'll use the command at the top of the page: ssh -p 2022 -l rob -i ~/.ssh/identity_work_rsa work-server.com. We're going to split it up and match it to the correct part of our config file.

We need a name for this connection, lets say Work, so lets add that to our config file:

# My work connection
  Host work
  

In the first part of the command we specify the port number, 2022, not the standard SSH port, so we'll need to make sure we explicitly add this to our config file:

# My work connection
  Host work
      Port 2022
  

I've added a 4 space indentation to show what lines apply to which host.

Next up we're adding which user we want to connect as:

# My work connection
  Host work
      Port 2022
      User rob
  

We're also using a different SSH key (identity file) to connect to this server, so lets add that:

# My work connection
  Host work
      Port 2022
      User rob
      IdentityFile ~/.ssh/identity_work_rsa
  

Last but by no means least, the hostname:

# My work connection
  Host work
      Port 2022
      User rob
      IdentityFile ~/.ssh/identity_work_rsa
      HostName work-server.com
  

Great! We've broken down a command into a configuration section. To get it working we need to save the file and restart the SSH daemon: sudo service sshd restart, you should now be able to run:

my-machine $ ssh work
  

and as if by magic you will get connected to that machine. Good eh?

You can do some more reading here on all the different configuration options you can use.

I do hope SSH'ing becomes a real verb one day.