SSH
Remote Access & File Transfer (How Engineers Work Across Machines)
As an engineer, you will often work with other computers:
- servers
- cloud machines
- lab systems
- remote Linux boxes
To do this securely, engineers use SSH and related tools.
What Is SSH?
SSH (Secure Shell) is a secure way to connect to another computer over a network.
It lets you:
- open a remote terminal
- run commands on another machine
- manage servers securely
Everything is encrypted.
Beginner Mental Model
Think of SSH as:
“A secure remote terminal.”
You type commands on your laptop — they run on another computer.
OpenSSH (The Most Common SSH Implementation)
OpenSSH is the most widely used software that provides SSH.
It comes in two main parts:
- openssh-client
- openssh-server
openssh-client (Connect to Other Computers)
The OpenSSH client is used when you want to connect to another machine.
Example:
Used for:
- logging into remote servers
- accessing cloud machines
- working on college lab systems
Most systems already have this installed.
openssh-server (Allow Others to Connect to You)
The OpenSSH server runs on the machine you want to connect to.
It allows:
- incoming SSH connections
- secure remote access
Used on:
- servers
- lab machines
- virtual machines
Without openssh-server, others cannot SSH into that machine.
Simple Difference
| Tool | Purpose |
|---|---|
| openssh-client | Connect to other machines |
| openssh-server | Allow others to connect to you |
What Is rsync?
rsync is a fast and efficient file transfer tool.
It copies files:
- locally
- between computers
- over SSH
Only changes are transferred, not the entire file.
Why Engineers Use rsync
⚡ Efficient Transfers
- Transfers only modified parts
- Saves time and bandwidth
🔐 Secure
When used with SSH, rsync is:
- encrypted
- safe for remote transfers
🔁 Reliable for Backups
Engineers use rsync for:
- syncing project folders
- backups
- moving large directories
Beginner Mental Model
Think of rsync as:
“Smart copy that works locally or remotely.”
Simple rsync Example
Copy a folder to a remote server:
Only changes are sent.
How Engineers Use These Together
Typical workflow:
- Use SSH to log into a server
- Use rsync to upload or download files
- Work remotely as if the machine is local
This is a core Linux skill.