Set up SSH shortcuts in macOS, Linux, and Raspberry Pi

January 23, 2019

WAIT This guide is for users who are using SSH keys. If, instead, you are using a username and password to connect to your remote machine, make sure you follow one of our guides to setting up keys before you start. We have how-to-switch guides for macOS, Linux, and Raspberry Pi.

Setting up shortcuts

This guide explains how you can set up SSH shortcuts on your Mac, Linux, or Raspberry Pi computer, and thereby avoid having to remember long strings of information each time you connect to a remote computer using SSH.

Typically, to "SSH in" to a given server, a user needs to type a string similar this one from the command line:

ssh -i /Users/ExampleUser/Keys/sshkeys/key.pem ubuntu@123.456.789.101

This string tells your computer:

  1. that you want to connect using SSH
  2. that you want to use an SSH key rather than a password
  3. that the SSH key you want to use is located at /Users/ExampleUser/Keys/sshkeys/key.pem
  4. that the username is ubuntu, and
  5. that the server is at IP address 123.456.789.101

— quite a lot of information for you to remember! If SSH is, say, set up on a custom port, this string can be even more complicated. By setting up a reference file in ~/.ssh/config you can bypass this headache completely and, instead, simply type ssh servernamefrom the command line each time you want to log in.

Here's how you do it.

Step 1

This guide assumes that you have already generated a set of SSH keys on your computer. If you have, you can skip this step. If you do not have a set of SSH keys installed on your local computer, you can generate one by running the following (replacing [note] with your own note, of course):


      ssh-keygen -t rsa -C "[note]"

There is no need to add a password to the key. This guide assumes that you will save the new keys in the suggested directory, which is ~/.ssh.

Step 2

Now, we can create some SSH shortcuts. To set up a new shortcut open the file at ~/.ssh/config. If there is no config file in the ~/.ssh folder, the act of opening it will create a blank one:


      sudo nano ~/.ssh/config

Step 3

Insert the variables you need into the ~/.ssh/config file.

The basic variables are:
Host This is the shortcut variable you will type after ssh, and should be something descriptive and memorable, e.g. webserver
HostName This is the IP address of the server to which you want to connect
User This is the username you will use to connect
Identity File This is the path of any SSH key you need (if you’re using your machine’s default key, rather than a key saved elsewhere within your folder structure, use ~/.ssh/id_rsa instead)
Port If you’re not using port 22, which is default for ssh, put in the alternative port number here

Advanced users can find the full list of config variables here.

Here is an example line:


      Host example-server
        HostName 123.456.789.101
        User ubuntu
        IdentityFile /Users/ExampleUser/sshkeys/serverkey.pem
        Port 3400

Step 4

Add any other servers you want to be able to access quickly. You can add as many lines as you need within the config file. For example:


      Host example-server
        HostName 123.456.789.101
        User ubuntu
        IdentityFile /Users/macuser/sshkeys/serverkey.pem
        Port 18166

Host example-server2
        HostName 123.456.789.102
        User root
        IdentityFile /Users/macuser/sshkeys/serverkey2.pem

In the above example, the example-server entry would connect to port 18166, while example-server2 would connect to the default port, which is 22.

Step 5

Save the config file.

Step 6

Before trying it out, make sure that the config file has the correct permissions:


      chmod 600 ~/.ssh/config

Step 7

Now, to connect to your server you can just type:


      ssh example-server

Much better.

Versions

macOS: 10.14.3
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