SCP — Secure Copy

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tags:

• network
• sysadmin

• linux

  SCP — Secure Copy Protocol

scp (Secure Copy) uses SSH to securely transfer files between hosts. While being deprecated in favor of SFTP, it remains widely used for quick file transfers due to its simple syntax. For incremental or large-scale transfers, consider rsync instead.

📚 Official Docs / Официальная документация: scp(1)

Basic Transfer

Upload to Remote

scp file.txt <USER>@<HOST>:/path/             # Copy file to remote / Скопировать файл на удалённый хост
scp file.txt <USER>@<HOST>:                   # Copy to home directory / Скопировать в домашнюю директорию
scp file1.txt file2.txt <USER>@<HOST>:/path/  # Copy multiple files / Скопировать несколько файлов
scp -r dir/ <USER>@<HOST>:/path/              # Copy directory recursively / Скопировать директорию рекурсивно
scp -r dir1/ dir2/ <USER>@<HOST>:/path/       # Copy multiple directories / Скопировать несколько директорий

Download from Remote

scp <USER>@<HOST>:/path/file.txt ./           # Copy from remote / Скопировать с удалённого хоста
scp <USER>@<HOST>:/path/file.txt ./local/     # Copy to local directory / Скопировать в локальную директорию
scp -r <USER>@<HOST>:/path/dir/ ./            # Copy directory from remote / Скопировать директорию с удалённого
scp <USER>@<HOST>:/path/\*.txt ./             # Copy with wildcard / Скопировать по маске

Copy Between Remotes

scp -3 <USER1>@<HOST1>:/p/file <USER2>@<HOST2>:/p/  # Copy between remotes via local / Между удалёнными через локальный
scp <USER1>@<HOST1>:/p/file <USER2>@<HOST2>:/p/     # Direct copy (no -3) / Прямое копирование

Advanced Options

Custom Port & Key

scp -P 2222 file.txt <USER>@<HOST>:/path/     # Custom SSH port / Пользовательский SSH порт
scp -i ~/.ssh/id_ed25519 file <USER>@<HOST>:/path/  # Specific SSH key / Конкретный SSH ключ
scp -P 2222 -i ~/.ssh/key file <USER>@<HOST>:/path/  # Port + key / Порт + ключ

Preserve Attributes

scp -p file.txt <USER>@<HOST>:/path/          # Preserve modification times / Сохранить время модификации
scp -rp dir/ <USER>@<HOST>:/path/             # Recursive with attributes / Рекурсивно с атрибутами

Limit Bandwidth

scp -l 1000 file.txt <USER>@<HOST>:/path/     # Limit to 1000 Kbit/s / Ограничить до 1000 Кбит/с
scp -l 8000 large.iso <USER>@<HOST>:/path/    # Limit to 8000 Kbit/s (1MB/s) / Ограничить до 8000 Кбит/с (1МБ/с)

Quiet & Verbose

scp -q file.txt <USER>@<HOST>:/path/          # Quiet mode / Тихий режим
scp -v file.txt <USER>@<HOST>:/path/          # Verbose mode / Подробный режим
scp -vvv file.txt <USER>@<HOST>:/path/        # Extra verbose / Очень подробный

Performance & Compression

Compression

scp -C file.txt <USER>@<HOST>:/path/          # Enable compression / Включить сжатие
scp -C big.iso <USER>@<HOST>:/path/           # Compress large file / Сжать большой файл
scp -C -r /large/dir <USER>@<HOST>:/path/     # Compress directory / Сжать директорию

Cipher Selection

scp -c aes128-ctr file <USER>@<HOST>:/path/   # Fast cipher / Быстрый шифр
scp -c aes256-ctr file <USER>@<HOST>:/path/   # Secure cipher / Безопасный шифр
scp -c [email protected] file <USER>@<HOST>:/path/  # Modern cipher / Современный шифр

[!NOTE] SCP does not support parallel transfers. Use rsync or pscp for parallel file transfer. / SCP не поддерживает параллельную передачу. Используйте rsync или pscp.

Troubleshooting

Debug Connection

scp -v file.txt <USER>@<HOST>:/path/          # Verbose output / Подробный вывод
scp -vvv file.txt <USER>@<HOST>:/path/        # Debug output / Отладочный вывод

Permission Issues

chmod 600 ~/.ssh/id_rsa                       # Fix key permissions / Исправить права ключа
ssh-add ~/.ssh/id_rsa                         # Add key to agent / Добавить ключ в агента

Test Connection

ssh <USER>@<HOST> "echo test"                 # Test SSH first / Сначала проверить SSH
ssh -p 2222 <USER>@<HOST>                     # Test custom port / Проверить пользовательский порт

Real-World Examples

Backup to Remote Server

# Backup directory
tar -czf - /data | ssh <USER>@<HOST> "cat > backup-$(date +%F).tar.gz"

# Or with scp
tar -czf backup.tar.gz /data
scp backup.tar.gz <USER>@<HOST>:/backups/backup-$(date +%F).tar.gz

Deploy Application

# Upload to multiple servers
for server in server1 server2 server3; do
  scp -r app/ <USER>@$server:/opt/app/
done

# Upload with compression
scp -C -r dist/ <USER>@<HOST>:/var/www/html/

Download Logs

# Download logs from remote
scp <USER>@<HOST>:/var/log/app/*.log ./logs/

# Download with date filter
ssh <USER>@<HOST> "find /var/log -name '*.log' -mtime -7 -print0" | xargs -0 -I {} scp <USER>@<HOST>:{} ./logs/

Sync Configuration Files

# Sync to multiple servers
for server in web1 web2 web3; do
  scp nginx.conf <USER>@$server:/etc/nginx/
  ssh <USER>@$server "sudo systemctl reload nginx"
done

Large File Transfer

# Transfer with compression and limit
scp -C -l 10000 large-db-dump.sql <USER>@<HOST>:/backups/

# Monitor progress with pv
pv large-file.iso | ssh <USER>@<HOST> "cat > /path/large-file.iso"

Database Backup & Transfer

# MySQL backup and transfer
mysqldump -u root -p<PASSWORD> database | ssh <USER>@<HOST> "cat > database-$(date +%F).sql"

# PostgreSQL backup and transfer
pg_dump database | ssh <USER>@<HOST> "cat > database-$(date +%F).sql"

Container Image Transfer

# Save and transfer Docker image
docker save myimage:latest | ssh <USER>@<HOST> "docker load"

# Transfer with compression
docker save myimage:latest | gzip | ssh <USER>@<HOST> "gunzip | docker load"

Copy Between Cloud Instances

# AWS to GCP / AWS
scp -i aws-key.pem -3 ec2-user@<AWS_IP>:/data/file.tar.gz user@<GCP_IP>:/data/

# With jump host
scp -o ProxyJump=<JUMP_HOST> file.txt <USER>@<TARGET_HOST>:/path/

Reference Tables

Common Options

Alternative Tools

[!IMPORTANT] SCP is being deprecated in favor of SFTP in future OpenSSH versions. Consider using rsync or sftp for new workflows. / SCP устаревает в пользу SFTP в будущих версиях OpenSSH. Используйте rsync или sftp для новых задач.

📚 Documentation Links

• scp Man Page