SSH Explanation

SSH in the terminal means Secure Shell.

It is a protocol used to securely connect from one computer to another over a network, most commonly to control a remote server through a command-line interface (the terminal).

What it’s used for

• Logging into remote servers
• Running commands on another machine
• Managing servers and cloud instances
• Transferring files securely (via SCP or SFTP)

Basic idea

You type an SSH command in your terminal, and it opens a secure, encrypted session to another computer.

Example

ssh user@server_address

• user = username on the remote machine
• server_address = IP address or domain name of the remote machine

Why it matters

• Encrypted (safe from eavesdropping)
• Replaces insecure methods like Telnet
• Standard tool in Linux, macOS, and developer workflows

Step-by-step example of using SSH

Step 1: Open a terminal

• Linux / macOS: Open Terminal
• Windows: Open PowerShell or Windows Terminal

Step 2: Make sure SSH is available

ssh -V

If SSH is installed, you will see a version number.

Step 3: Connect to a remote server (password login)

ssh username@server_ip

Example

ssh john@192.168.1.50

1. The terminal tries to connect to the server.
2. You may be asked to trust the host.
3. Enter the user’s password.
4. You are now logged into the remote machine.

Step 4: Run commands on the remote server

ls
pwd
uptime

Step 5: Exit the SSH session

exit

or press Ctrl + D

Step 6: Use SSH keys instead of passwords (Recommended)

Generate a key

ssh-keygen

• Private key: ~/.ssh/id_rsa
• Public key: ~/.ssh/id_rsa.pub

Copy the public key to the server

ssh-copy-id username@server_ip

Log in using the key

ssh username@server_ip

Main applications of SSH

1. Remote login and server administration

• Administering Linux servers
• Managing cloud servers
• Controlling servers remotely

2. Secure remote command execution

ssh user@server "df -h"

3. Secure file transfer

scp file.txt user@server:/home/user/
sftp user@server

4. Tunneling and port forwarding

Used for secure access to internal services.

5. Version control access

Used with GitHub, GitLab, Bitbucket.

6. Automation and scripting

ssh user@server "sudo apt update && sudo apt upgrade -y"

Git + SSH

git clone git@github.com:username/project.git

Automation with SSH

ssh user@server "uptime"

Summary

• Secure remote access
• Secure file transfer
• Automation and deployment
• Encrypted tunneling
• Authentication for developer tools

Further Reading

1.