---
title: scp — remote file copy
date: 2026-10-18
time: 12:00
model: admin
category: programs
author_type: human
summary: A command that copies files between local and remote systems using ssh. Convenient for small transfers.
tags: program, Remote server connection management, scp
---

**💬 "scp command"**

scp is file copying that operates over ssh. It is the simplest way to move one or two files.

For bulk or incremental transfers, rsync is better; scp is used for simple transfers.

- **Concept**: Uses ssh authentication as-is to copy files.
- **Left argument**: Source path. If remote, `user@host:/path`.
- **Right argument**: Destination path.
- **Direction**: Both local→remote and remote→local are possible.
## Frequently used options

| Option | Description |
| --- | --- |
| -P <port> | Specifies the SSH port (uppercase P) |
| -i <key> | Specifies the key to use |
| -r | Copies directories recursively |
| -C | Compresses during transfer |

## Three essential command combinations

- `scp -i ~/.ssh/deploy app.tgz deploy@10.0.0.9:/tmp/` — Send the release file to the server
- `scp -P 22022 deploy@10.0.0.9:/var/log/app/error.log ./` — Fetch the server log to the local machine
- `scp -r -i ~/.ssh/deploy ./conf deploy@10.0.0.9:/tmp/conf` — Transfer the entire configuration directory
**💬 "Tell me common real-world mistakes and how to avoid them"**

Here are common situations on live production servers, in order.

### Step 1 · Transfer

Send the file to the target server.

```
scp -i ~/.ssh/deploy app-20261018.tgz deploy@10.0.0.9:/tmp/
```

### Step 2 · Verification

Compare the size and checksum.

```
ssh deploy@10.0.0.9 'md5sum /tmp/app-20261018.tgz' && md5sum app-20261018.tgz
```

### Step 3 · Apply

After verification, proceed with the deployment procedure.

```
ssh deploy@10.0.0.9 'tar xzf /tmp/app-20261018.tgz -C /opt/app/releases/20261018'
```

## How this is used in practice

### 1. Transferring release files

**Situation** — Sending artifacts from the build server to the production server.

```
scp -i ~/.ssh/deploy dist/app.tgz deploy@10.0.0.9:/tmp/
```

**Result** — The file is transferred to /tmp and progress is displayed.

**Point** — Comparing checksums after transfer catches corrupted transfers immediately.

### 2. Retrieving incident logs

**Situation** — You need to analyze production server logs locally.

```
scp -i ~/.ssh/deploy deploy@10.0.0.9:/var/log/app/error.log /tmp/srv01-error.log
```

**Result** — The logs are copied locally so you can analyze them with convenient tools.

**Point** — For large logs, compress them before downloading or grep only the section you need.

## Things to watch out for

- The port option is uppercase -P (ssh uses lowercase -p).
- scp does not support resuming or incremental transfer, so it is inefficient for large files.
- By default, scp does not fully preserve permissions and ownership.
- Do not overwrite production paths directly; download to /tmp and verify.
## Actual execution screen

This is the result of transferring the release file and verifying its checksum.

![scp command execution result: file transfer and checksum](https://games.aidebatehub.com/assets/scp-demo.png)

Live production server

---
Source (HTML): https://games.aidebatehub.com/programs/linux/remote/scp.html
This file is an auto-generated Markdown twin of the DevHub document.