SCP - Secure Copy¶

Overview¶

SCP (Secure Copy Protocol) copies files between hosts over SSH. Simple, secure, and available wherever SSH is.

┌──────────────────────────────────────────────────────────────────────────┐
│                           SCP Transfer                                    │
│                                                                           │
│   Local Machine                              Remote Server                │
│   ┌─────────────────┐                       ┌─────────────────┐          │
│   │                 │      SSH Tunnel       │                 │          │
│   │   file.txt     ─┼──────────────────────▶│    file.txt     │          │
│   │                 │      Encrypted        │                 │          │
│   └─────────────────┘                       └─────────────────┘          │
│                                                                           │
└──────────────────────────────────────────────────────────────────────────┘

Basic Syntax¶

scp [options] source destination

Locations can be: - Local: /path/to/file - Remote: user@host:/path/to/file

Copy To Remote¶

Single File¶

scp file.txt user@host:/home/user/
scp file.txt user@host:~/
scp file.txt user@host:~/newname.txt

Multiple Files¶

scp file1.txt file2.txt user@host:~/
scp *.txt user@host:~/documents/

Directory¶

scp -r directory/ user@host:~/
scp -r directory/ user@host:~/newdirname/

Copy From Remote¶

Single File¶

scp user@host:/path/to/file.txt ./
scp user@host:~/file.txt ./local_name.txt

Multiple Files¶

scp user@host:~/file1.txt user@host:~/file2.txt ./
scp "user@host:~/*.txt" ./

Directory¶

scp -r user@host:~/directory/ ./

Copy Between Remote Hosts¶

scp user1@host1:/path/file.txt user2@host2:/path/

Routing

By default, traffic goes through your local machine. Use -3 to force this, or configure ProxyJump for direct transfer.

Common Options¶

Port¶

scp -P 2222 file.txt user@host:~/

Identity File¶

scp -i ~/.ssh/mykey file.txt user@host:~/

Recursive (Directories)¶

scp -r directory/ user@host:~/

Preserve Attributes¶

scp -p file.txt user@host:~/
# Preserves modification times, access times, modes

Compression¶

scp -C largefile.tar.gz user@host:~/

Bandwidth Limit¶

scp -l 1000 file.txt user@host:~/
# Limit in Kbit/s (1000 Kbit/s = ~125 KB/s)

Quiet Mode¶

scp -q file.txt user@host:~/

Verbose¶

scp -v file.txt user@host:~/

Using SSH Config¶

SCP uses ~/.ssh/config:

# ~/.ssh/config
Host myserver
    HostName server.example.com
    User admin
    IdentityFile ~/.ssh/server_key
    Port 2222

Then simply:

scp file.txt myserver:~/
scp myserver:~/file.txt ./

Through Jump Host¶

With ProxyJump¶

scp -o ProxyJump=bastion file.txt internal:~/

Using Config¶

# ~/.ssh/config
Host internal
    HostName 10.0.0.10
    User admin
    ProxyJump bastion

scp file.txt internal:~/

Progress and Statistics¶

Show Progress (Default)¶

scp file.txt user@host:~/
# Shows: file.txt    100%  1234KB  10.5MB/s   00:00

Hide Progress¶

scp -q file.txt user@host:~/

Handling Special Characters¶

Spaces in Paths¶

# Quote the entire remote path
scp "user@host:~/path with spaces/file.txt" ./

# Or escape
scp user@host:~/path\ with\ spaces/file.txt ./

Special Characters¶

scp "user@host:~/file[1].txt" ./
scp user@host:"~/file[1].txt" ./

Large File Transfers¶

With Compression¶

scp -C largefile.iso user@host:~/

Resumable (Not Native)¶

SCP doesn't support resume. For large files, use rsync instead:

rsync -avP --partial largefile.iso user@host:~/

Monitor Progress with pv¶

# Alternative approach
cat largefile.iso | pv | ssh user@host "cat > largefile.iso"

Batch Operations¶

Multiple Hosts¶

for host in server1 server2 server3; do
    scp file.txt user@$host:~/
done

Multiple Files with Wildcards¶

scp user@host:"/var/log/*.log" ./logs/

From File List¶

while read file; do
    scp "$file" user@host:~/backup/
done < filelist.txt

Exit Codes¶

Code	Meaning
0	Success
1	General error
2	Connection error
65	Host not allowed
66	Protocol error

Comparison with Alternatives¶

Feature	SCP	SFTP	rsync
Simple copies	✅	✅	✅
Interactive	❌	✅	❌
Resume transfers	❌	✅	✅
Delta sync	❌	❌	✅
Preserve permissions	✅	✅	✅
Bandwidth limit	✅	✅	✅
Available everywhere	✅	✅	⚠️

When to Use SCP¶

Use SCP for: - Quick, simple file copies - Small to medium files - One-off transfers - Scripts needing simple syntax

Use SFTP for: - Interactive file management - Browsing remote directories - Resume support

Use rsync for: - Large files (resume support) - Directory synchronization - Incremental backups - Bandwidth optimization

Troubleshooting¶

Permission Denied¶

# Check remote permissions
ssh user@host "ls -la ~/target/"

# Check you're using correct user
scp file.txt correctuser@host:~/

Connection Refused¶

# Test SSH connection first
ssh user@host

# Check port
scp -P 2222 file.txt user@host:~/

Slow Transfers¶

# Enable compression
scp -C file.txt user@host:~/

# Check network
ssh user@host "speedtest-cli"

Path Issues¶

# Use absolute paths
scp file.txt user@host:/home/user/

# Quote paths with spaces
scp file.txt "user@host:/path with spaces/"

Security Considerations¶

Uses SSH encryption - Traffic is secure
Respects SSH config - Same security as SSH
Key-based auth - Use keys, not passwords
Verify host keys - Don't skip host key verification

# Bad (skips verification)
scp -o StrictHostKeyChecking=no file.txt user@host:~/

# Good (uses verification)
scp file.txt user@host:~/