Get to the Opus Command Line

This lab will get you to the Opus command line from your home or school computer. The process is different depending on your operating system, and there may be multiple ways to do it. To access Opus you need the Zip file that was mailed to you in the Canvas Inbox. This lab is an essential first step toward accessing the materials for the course.

This lab has instructions for:

• Windows 10+

• OSX

• Linux

Step 1: Install Your SSH Key

In Canvas send you a Zip file that contains three files:

1. config - This is an SSH configuration file.

2. id_ed25519 - This is a private key.

3. id_ed25519.pub - This is a public key.

These files need to be installed on your computer in a folder called .ssh that’s located in your home folder. If you’ve never used the ssh command before the folder won’t exist. In this step you’ll create the folder and move the files into it. Follow the steps for your operating system.

OSX

1. Click Go in the top menu bar, then select Home.

2. Press Command + Shift + . (period) to show hidden files

3. In the top menu click File then New Folder to create a folder named .ssh.

4. Drag and drop the files inside of the Zip file into the .ssh folder.

Windows 11

1. Open File Explorer from the taskbar

2. Select View -> Show, then select Hidden items to view hidden files and folders

3. Navigate to your home folder in File Explorer:

   1. Click This PC

   2. Double click C:

   3. Double click the Users folder

   4. Double click the folder that’s named for your Windows user

4. In File Explorer click New -> Folder then create a folder named .ssh

5. Double-click the .ssh folder to enter into it

6. Drag and drop the files inside of the Zip file into this directory

Windows 10

1. Open File Explorer from the taskbar

2. Select View -> Options -> Change folder and search options

3. Select the View tab and, in Advanced settings, select Show hidden files, folders, and drives and OK

4. Navigate to your home folder in File Explorer:

   1. Click My Computer

   2. Double click C:

   3. Double click the Users folder

   4. Double click the folder that’s named for your Windows user

5. In File Explorer click New -> Folder then create a folder named .ssh

6. Double-click the .ssh folder to enter into it

7. Drag and drop the files inside of the Zip file into this directory

Linux

1. Open your file manager (Dolphin or GNOME) and enable the display of hidden files by pressing Ctrl + H.

2. Navigate to your home directory by clicking Home on the left.

3. Right click and select New Folder to create a directory called .ssh.

4. Drag and drop the files inside of the Zip file into this directory.

Step 2: Start a Terminal

Starting a terminal is different depending on your operating system. Once you have started a terminal the commands are similar:

Windows 10+:

Use the Start menu:

Start -> Search for “PowerShell”

Warning

Do not start the “PowerShell ISE” command or run PowerShell as Administrator. Those won’t work.

Macintosh OSX

Applications -> Utilities -> Terminal

You can also launch a terminal with the Command + T key sequence.

Linux

Linux often comes with a terminal shortcut in the menu bar. You can usually also start one with:

Ctrl + Shift + T

Step 3: SSH into Opus

I have created a server that’s used for class assignments. The server is called opus.cis.cabrillo.edu. The SSH program makes a secure connection between your computer and opus. The secure connection enables you to run commands on opus. Using the command line on your computer run the following command:

OSX and Linux

On OSX and Linux you need to run the following command to fix the permissions on your ~/.ssh directory:

chmod -R go-rwx ~/.ssh

You only have to do this once.

If the files are installed and the permissions are correct you should now be able to use SSH to connect to opus:

ssh opus.cis.cabrillo.edu 

The first time you run the ssh command it will ask you if it’s okay to connect. Answer y or yes.

Do you notice that the prompt has changed?

Take a screenshot of your opus shell.

Turn In

Turn in the screenshot from step 3.