Turning Commands Into a Bash Script

30 minutes
  • 4 Learning Objectives

About this Hands-on Lab

In this hands-on lab, we’re going to write a shell script for connecting to Linux Academy Linux servers from another Linux (or Mac) host, without having to first accept the RSA fingerprint.

Learning Objectives

Successfully complete this lab by achieving the following learning objectives:

Determine What Options Should Be Used with the ssh Command

View the man page for the ssh command, and determine the option to use to disable host key checking.

Build a Script from the Required Commands
  1. Create a bin folder in cloud_user‘s home directory.

    mkdir bin
  2. Use Vim to create the file lab.sh in the new bin folder.

    vim bin/lab.sh
  3. Create the following script.

    if [ -n $1 ]
      ssh -o StrictHostKeyChecking=no $login_user@$1
  4. Then, save the file by running.

Execute and Verify the Script
  1. Save the file, and make it executable.

    chmod u+x bin/lab.sh
  2. Run the script, passing as the first parameter to be assigned to $1.

  3. Press Ctrl + C to exit the password prompt.

Add the New bin Directory to the PATH Variable
  1. Append to the .bashrc file in cloud_user‘s home directory to add the new bin folder to the PATH environment variable.

    echo 'PATH="$HOME/bin:$PATH"' >> .bashrc
  2. Source .bashrc to pick up the change.

    . .bashrc
  3. Verify that you can run lab.sh without specifying the path to the script.


Additional Resources

Your supervisor is tired of having to accept the RSA key fingerprint every time they log in to a new hands-on lab. They've asked you to write a shell script that can be run from their local Linux desktop to connect to these servers without prompting to accept the key.

What are Hands-on Labs

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.

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