Secure File Transfer &

Remote Access

A Plain-Language Guide to SSH, SCP, and rsync

What is This About?

When you work with computers — especially across different machines, servers, or networks — you often need to move files from one place to another or control a machine remotely. This guide explains three tools that IT professionals and engineers use to do exactly that, in plain language you can understand without a technical background.

SSH — Remote Control of a Computer

SSH stands for Secure Shell. It lets you connect to another computer over the internet or a local network and control it using text commands — as if you were sitting in front of it.

What can you do with SSH?

• Open a terminal window on a remote server or another computer
• Run programs, manage files, or check system status remotely
• Use it as the foundation for transferring files securely (which is how SCP and rsync work)

Key features

• Fully encrypted — no one can intercept your session
• Works on local networks (e.g. office LAN) and across the internet
• Can use a password or a secure digital key (like a badge instead of a PIN)

SCP — Quick, Simple File Copying

SCP (Secure Copy) is a tool for copying files between computers over SSH. It's fast to use and has a straightforward approach: pick a file, pick a destination, and it copies.

Best used for...

• One-off file transfers — sending a report, log file, or document to another machine
• Situations where simplicity matters more than efficiency
• Copying a single file or a small folder quickly

Limitations to be aware of

• If a file already exists on the destination, it copies the entire file again anyway — no shortcut
• If the transfer is interrupted (e.g. network drops), you must start from scratch
• Cannot skip or exclude specific files or folders

rsync — Smart, Efficient File Synchronisation

rsync is a more intelligent version of SCP. Instead of copying everything every time, it compares what is on the source and destination and only transfers what is new or has changed. This is called delta transfer.

Best used for...

• Regular backups or syncing a project folder between machines
• Large folders where most files do not change between transfers
• Situations where transfers might get interrupted and need to resume
• Keeping two locations in sync, including deletions

Key advantages over SCP

• Only transfers what changed — dramatically faster for repeated syncs
• Can resume from where it left off if interrupted
• Can mirror deletions — if a file is removed from the source, it can be removed from the destination too
• Supports excluding certain files or folders (e.g. skip temporary files or build outputs)

Side-by-Side Comparison

Here is how SCP and rsync compare on the features that matter most:

Same Network vs. Remote Access

Whether you are on the same office network or connecting from another city, these tools work the same way. The only difference is how you identify the target machine:

Setup Checklist

If you want to receive connections on a machine (so someone can SSH into it, or copy files to it), here are the steps:

Summary

All three tools work together as a family:

• SSH provides the secure foundation and lets you remotely control a machine
• SCP uses SSH to copy individual files quickly and simply
• rsync uses SSH to synchronise folders intelligently, only transferring what changed

For most real-world use cases — especially backups, project syncing, or anything you do repeatedly — rsync is the right choice. For a quick one-time file transfer, SCP is perfectly fine.

All three are industry-standard tools, widely used by engineers, developers, and system administrators across all types of organisations worldwide.