Secure Shell, commonly abbreviated as SSH, is a pivotal protocol in the realm of secure communication over networks. Developed as a secure alternative to traditional, less secure protocols like Telnet, SSH establishes a secure connection between two devices, typically a client and a server.

What is SSH ?

SSH, also known as Secure Shell or Secure Socket Shell, is a network protocol that gives users, particularly system administrators, a secure way to access a computer over an unsecured network. It also refers to the suite of utilities that implement the SSH protocol. Secure Shell provides strong password authentication and public key authentication, as well as encrypted data communications between two computers connecting over an open network, such as the internet.

How does SSH work?

It was created to replace insecure terminal emulation or login programs, such as Telnet, rlogin (remote login) and rsh (remote shell). It enables the same functions — logging in to and running terminal sessions on remote systems. Also it replaces file transfer programs, such as File Transfer Protocol (FTP) and rcp (remote copy).

It is to establish a secure connection between two devices, typically a client and a server, allowing data to be exchanged securely. it achieves this through the use of strong encryption algorithms, ensuring confidentiality, integrity, and authentication of the transmitted data.

What is SSH used for?

Present in all data centers, SSH ships by default with every Unix, Linux and Mac server. SSH connections have been used to secure many different types of communications between a local machine and a remote host, including secure remote access to resources, remote execution of commands, delivery of software patches, and updates and other administrative or management tasks.

In addition to creating a secure channel between local and remote computers, SSH is used to manage routers, server hardware, virtualization platforms, operating systems (OSes), and inside systems management and file transfer applications.

Secure Shell is used to connect to servers, make changes, perform uploads and exit, either using tools or directly through the terminal. SSH keys can be employed to automate access to servers and often are used in scripts, backup systems and configuration management tools.

Secure Shell capabilities

Functions that enables include the following:

secure remote access to SSH-enabled network systems or devices for users, as well as automated processes;

• secure and interactive file transfer sessions;
• automated and secured file transfers;
• secure issuance of commands on remote devices or systems; and
• secure management of network infrastructure components.

SSH can be used interactively to enable terminal sessions and should be used instead of the less secure Telnet program. SSH is also commonly used in scripts and other software to enable programs and systems to remotely and securely access data and other resources.

15 Basic SSH Commands

SSH commands are a type of Unix command or shell procedure. They are the basic tools used to interact with Linux on an individual level. Its used to perform a variety of tasks, including displaying information about files and directories.

Here I have put all Basic Linux Commands that every Linux user (as a beginner) should know. These are the basic and most commonly used commands.

Commands	Functions
cat	Concatenate and display the contents of files.
cd	Change directory
cd..	To move the previous directory
cp	Copy the file from one directory to another directory
du	Show disk usgae
kill	Kill/terminate the system process
rmdir	Remove the directory
mkdir	Create a directory
top	Monitor the system performance in real time.
ls	List out the files
mv	Move the files from one directory to another directory
vi	Edit the file
netstat	shows current network connections
pwd	Display the current working directory
locate	Find a file in the server

Final thoughts

In summary, Secure Shell is a critical and widely adopted protocol that plays a pivotal role in secure communication and remote access in computing environments. Its robust features, adaptability, and ongoing development make it a reliable and indispensable tool for anyone dealing with networked systems and the need for secure remote connections.