Imagine sitting at your computer in Dallas and controlling a computer in New York, London, or Tokyo. That's what SSH allows you to do.

 

SSH in 3 Minutes 🔑

Imagine sitting at your computer in Dallas and controlling a computer in New York, London, or Tokyo.

That's what SSH allows you to do.

SSH is one of the most important tools in Linux, cloud computing, and Raspberry Pi projects.

---

📌 Key Term

SSH

Secure Shell, a protocol used to securely connect to another computer over a network.

---

What SSH Does

SSH allows you to:

• Log into remote computers
• Run commands remotely
• Transfer files
• Manage servers

It's commonly used with:

• Linux
• Ubuntu
• Raspberry Pi
• AWS EC2

---

A Typical SSH Command

ssh ubuntu@192.168.1.50

In this example:

• ssh starts the SSH client
• ubuntu is the username
• 192.168.1.50 is the destination computer

If the connection succeeds, you'll receive a command prompt on the remote machine.

---

📌 Remember

SSH gives you access to another computer's command line.

Treat that access carefully.

---

Passwords vs Keys

SSH can use passwords, but modern systems often use SSH keys.

A key pair consists of:

• A private key
• A public key

The public key goes on the server.

The private key stays with you.

---

📌 Key Term

SSH Key

A cryptographic credential used to authenticate securely without a password.

---

AWS Example

Connecting to an EC2 instance often looks like this:

ssh -i my-key.pem ec2-user@54.123.45.67

The -i option specifies the key file.

Without the correct key, the connection will fail.

---

Common Problems

Connection Refused

The SSH service may not be running.

Permission Denied

The username or SSH key may be incorrect.

Timeout

A firewall or security group may be blocking access.

---

📌 Common Mistake

Using the wrong username.

Ubuntu instances often use:

ubuntu

Amazon Linux often uses:

ec2-user

---

The Big Idea

SSH is the remote control of the Linux world.

Whether you're managing a Raspberry Pi in your home, an Ubuntu server in the cloud, or an AWS EC2 instance, SSH is often the first tool you'll reach for.

Learn SSH once and you'll use it for years.

---

---

Aaron Rose is a software engineer and technology writer at tech-reader.blog. 

Catch up on the latest explainer videos, podcasts, and industry discussions below.