Gain insights into the command-line interface, delve into navigating file systems, creating scripts, and automating tasks to enhance productivity and control your computer efficiently.

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In this course, you will get the chance to explore the command-line interface (CLI), starting with basics like navigating file systems and working with directories and files. Then, you will use those building blocks to tackle more advanced features and tasks within the CLI. You will also learn to turn basic commands into executable scripts and easily automate common tasks. This course will empower you to put the interface to work, take complete control of your computer, and hack your way to productivity.

Harnessing the Power of the Command-Line Interface

# SSH

**Secure Shell**, or **SSH**, is an encrypted and secure method for logging in to remote machines. We can also use it to execute commands remotely and use related tools to copy files securely.

This is the standard way to log in to remote Linux servers, either in our own data center or in the cloud. In this lesson, we’ll use our local machine to connect to our Ubuntu virtual machine.
# Setting up SSH

First, we install the `openssh-server` package and enable SSH connections:


```
sudo apt install openssh-server
```

This installs and activates the SSH server on port `22`.

We identify the IP address of our Ubuntu machine using the `ip addr` command. We then use `grep` to look for `inet` in the output, filtering out `inet6` so we don’t see the IPv6 addresses:


```
ip addr | grep inet | grep -v inet6
```

# Establishing a connection

For simplicity, we’re going to cover how to establish a connection between two users on our platform.


To use SSH, we specify the username and server address to which we wish to connect:


```bash
ssh {username}@{ip}
```

The first time we connect to a remote host, SSH asks us to verify the authenticity of the host. Answering `yes` saves the fingerprint of the remote server to a file named `~/.ssh/known-hosts`. If the server’s fingerprint changes, we won’t connect to it because SSH will assume the machine has either been compromised or is a different machine. It’s just an extra security precaution; the fingerprint shouldn’t change without us expecting it.


Once we add the server to the list of known hosts, we’re prompted for our remote user’s password. Once we enter it, we’re logged in.


Here are the steps we must follow:





1. Upon the first prompt, enter `123456` as the password.
 
2. Type `su sshuser`.
3. Type `ssh temp@127.0.0.1`.
4. Upon the next prompt, type `yes` and press "Enter".
5. Finally, enter the password you set earlier and press "Enter".

Run the complete code on the terminal below for practice.
```
service ssh start
clear
passwd temp
```   

Learn how to use SSH to connect to remote machines.


Using Secure Shell to Connect to Remote Machines

Learn how to use SSH to connect to remote machines.

Introduction

Creating an Ubuntu Virtual Machine with VirtualBox

Navigating the Filesystem

Working with Files and Directories

Streams Of Text

The Shell and Environment

Running and Managing Programs

Networking Tools

Automation

Additional Programs

Conclusion

Using Secure Shell to Connect to Remote Machines

SSH