Remote File Editing with Sublime

Very , Very, VERY IMPORTANT WARNING

If you use VS Code as your editor/IDE you will may into major issues in this class that we cannot resolve. The issue is that VS Code does not behave nicely when editing files on a remote machine, which you will need to do in almost every assignment. For this reason, I very strongly recommend you use a different editor (like Sublime Text). See below for details.


As the class progresses, you will find yourself doing most/all of your work directly on EC2 instances. Hence, a common request is to easily create an ssh/sftp connection between the text editor on your local machine and an EC2 instance, so you can edit files on the remote machine as if they were local. Depending on the editor you use, there may be a remote editing plug-in available that allows you to do just that.

If you use Sublime Text, I already have the rmate package included in the class base AMI. In order to enable remote editing you just need to do the following on your MacOS or Linux laptop (see below for Windows):

  1. Install the rsub plug-in for Sublime Text, available through the Package Control tool:
    • Go to Tools → Command Palette → Package Control: Install Package.
    • Type ‘rsub’ and install.

  2. Configure remote port forwarding for the EC2 instance in your ~/.ssh/config file to enable the connection. The easiest approach is to forward the port for all remote hosts (so that you don’t need to update it as your instance DNS name changes):
    Host *
    Hostname %h
    RemoteForward 52698 127.0.0.1:52698

  3. Now, make sure Sublime is already open on your laptop, connect to the EC2 instance, and edit a file on your instance as follows: rmate <filename_to_edit>. If it’s a system/root-owned file, you must use: sudo rmate <filename_to_edit>.

  4. Alternatively, there are a few free sftp clients available that can be configured to open files in a local editor. If you don’t mind paying for software, try Transmit which I’ve used for years—it has great connectivity options and even allows you to browse your Amazon storage directly, which will come in handy later on in the course.

Using Sublime for Remote Editing on Windows

Additional configuration is required to use Sublime for remote editing on Windows.

  1. Convert your private SSH key from .ppk to .pem format. If you generated your AWS keypair in .ppk format you will need to convert it to .pem (or OpenSSH) format using PuTTYgen by following the instructions here. PuTTYgen was installed when you installed PuTTY, but if not, you will need to install it separately. Note: When exporting the key you should use the “Conversions” → “Export OpenSSH key (force new file format)” option.

  2. Set up the rsub package in Sublime; on Windows the installation is slightly different to that described above.
    • Go to Preferences → Package Control: Install Package.
    • Type ‘rsub’ and install.
    • Confirm the installation by checking that rsub is listed in Preferences → Package Settings.

  3. In a PowerShell window run the following command:
    PS C:\Users\userfoo> ssh -R 52698:127.0.0.1:52698 ubuntu@<DNS_name_or_IP_address> -i <full_path_to_your_.pem_key>
    where <DNS_name_or_IP_address> is the instance on which you wish to edit files.

  4. On your instance, edit files as above: code rmate <filename_to_edit> or sudo rmate <filename_to_edit>