# Copying Between Computers: scp and rsync

scp copies a file or two to or from another computer, and rsync sends a whole folder but only what changed; both write the other computer's side as host:path, with a colon, and rsync -n rehearses first.

Journeyman · Unix · Linux · Updated November 10, 2026

## After this lesson you can

- Copy a file to or from another computer with scp, writing the other side as host:path
- Send a folder to another computer with rsync -av over SSH, rehearsing with -n first

## Key takeaways

- host:path is a file on another computer. The colon is the border, and a path after it starts in your home folder there.
- scp FILE host:path sends a file and scp host:path . brings one back; -r copies a folder. Without the colon, scp copies on your own computer.
- rsync -av site/ host:folder/ sends a folder over SSH, and after the first time only what changed. The slash after site means "what's inside it".
- Add -n to rehearse and read the list before anything is copied.

Sam fixed the meetings page on the laptop. Now it has to get to the book club's server. You could log in with `ssh` and type the page again in nano, but the file is already written: it needs copying, not retyping. Two commands copy over SSH, with the same keys and short names: `scp` for a file or two, and `rsync` for a whole folder. The same jobs come up at work every week: putting a website live, fetching a log file from a server, sending a folder of data to a bigger computer.

## The book club's site

The examples use a small practice site, and the short name `bookclub` from *SSH Keys and ~/.ssh/config*. Its server is your own computer, so "the server's" copies land in your home folder, and the output shown in this lesson is what these commands print with `bookclub` pointing at localhost. Make the site:

```bash
mkdir -p ~/terminal-practice/book-club/site/images && cd ~/terminal-practice/book-club
printf '<h1>Maple Street Book Club</h1>\n<p>We meet on the first Tuesday of every month.</p>\n' > site/index.html
printf '<h1>Meetings</h1>\n<p>December: The Hobbit</p>\n' > site/meetings.html
printf 'The Hobbit\nLittle Women\nFrankenstein\n' > site/reading-list.txt
touch site/images/cover.jpg
ls site
```

```text
images  index.html  meetings.html  reading-list.txt
```

## host:path, the other computer's side

To name a file on another computer, write the computer, a colon and the path: `bookclub:bookclub-site/index.html`, read "on bookclub, the file bookclub-site/index.html". This is a **remote path**. A path after the colon starts in your home folder there; one that starts with `/` is absolute, such as `bookclub:/var/www`. `bookclub:` with nothing after the colon is your home folder there.

The colon is the whole difference. Leave it out, and the copy never leaves your computer:

```bash
scp site/index.html bookclub
ls
```

```text
bookclub  site
```

No error, no warning: `scp` made a local file named `bookclub`. Delete it with `rm bookclub`, and look for the colon whenever a copy "worked" but never arrived.

## scp: a file there, a file back

`scp` (*secure copy*) works like `cp`, from and to, with one side on another computer:

```bash
scp site/meetings.html bookclub:                    # send a file to your home folder there
scp bookclub:bookclub-site/reading-list.txt .       # bring one back into this folder
scp -r site bookclub:site-copy                      # -r: a whole folder
```

Each file shows a progress line while it travels. `scp` copies everything you name, every time, so for a folder you send again and again, use `rsync`.

## rsync: a whole folder, only what changed

The `rsync` from *Backups That Work: rsync* copies between computers too. Put a host and a colon in front of one side, and it goes over SSH. `-a` keeps folders, dates and permissions, and `-v` lists each file. Rehearse first: `-n` (a **dry run**) lists what would be copied and copies nothing:

```bash
rsync -avn site/ bookclub:bookclub-site/
```

```text
sending incremental file list
created directory bookclub-site
./
index.html
meetings.html
reading-list.txt
images/
images/cover.jpg

sent 209 bytes  received 71 bytes  560.00 bytes/sec
total size is 167  speedup is 0.60 (DRY RUN)
```

The list is right, so send it for real: the same command without `-n`. Then add a line to one page and send the folder again:

```bash
rsync -av site/ bookclub:bookclub-site/
printf '<p>January: Little Women</p>\n' >> site/meetings.html
rsync -av site/ bookclub:bookclub-site/
```

```text
sending incremental file list
created directory bookclub-site
./
index.html
meetings.html
reading-list.txt
images/
images/cover.jpg

sent 540 bytes  received 143 bytes  1,366.00 bytes/sec
total size is 167  speedup is 0.24
sending incremental file list
meetings.html

sent 317 bytes  received 42 bytes  718.00 bytes/sec
total size is 196  speedup is 0.55
```

The second time, only `meetings.html` traveled. Your byte counts may differ a little. For a site with hundreds of photos, that's the difference between seconds and minutes.

## The slash after site

`site/` with a slash means "what's inside site"; `site` without one means "the folder site itself". On your own computer, side by side:

```bash
rsync -a site/ backup
rsync -a site backup2
ls backup backup2
```

```text
backup:
images  index.html  meetings.html  reading-list.txt

backup2:
site
```

Across computers it's the same: `rsync -av site bookclub:bookclub-site/` puts the pages in `bookclub-site/site/`, where the web server won't look. Delete the two practice copies with `rm -r backup backup2`.

## Check yourself

2 questions to try on the lesson page.

## So what

`scp` sends a file and `rsync` sends a folder, both with the other computer written as `host:path`. Rehearse with `-n`, mind the slash, and the server gets exactly what you meant.

## Key terms

- [scp](https://www.ask-codey.com/glossary/scp)
- [rsync](https://www.ask-codey.com/glossary/rsync)
- [Remote Path](https://www.ask-codey.com/glossary/remote-path)
- [Dry run](https://www.ask-codey.com/glossary/dry-run)

## Cheat sheets

- [Copying Between Computers: scp and rsync](https://www.ask-codey.com/cheat-sheets/bash-copying-between-computers-cheat-sheet)

## Related

- [SSH Keys and ~/.ssh/config](https://www.ask-codey.com/lessons/bash-ssh-keys)
- [Backups That Work: rsync](https://www.ask-codey.com/lessons/bash-rsync)
- [Running Commands on Another Computer](https://www.ask-codey.com/lessons/bash-remote-commands)

Source: https://www.ask-codey.com/lessons/bash-copying-between-computers