# What is SCP?

If you need to transfer files quickly and securely between two machines using SSH, scp (Secure Copy Protocol) is the ideal command-line tool for the job. Designed for encrypted transfers, it is simple to use and highly effective, especially for one-off tasks.

The basic structure of an scp command is:

scp [options] <source> <destination>

# What do you need before using SCP?

Before transferring files with scp, you need to make sure you can authenticate to the remote server using SSH. This can be done in two main ways:

1. With a password: When you run scp, you will be prompted for the remote user’s password.
2. With SSH keys: Set up a public key on the remote server (usually in ~/.ssh/authorized_keys) and use your local private key to authenticate without a password. This is more secure and convenient for frequent use.

To test the connection, use:

ssh user@server

# Some practical examples

Send a file to a remote server

scp file.txt user@server:/remote/path/

This command will send file.txt to the remote server at the specified path.

Download a file from a remote server

scp user@server:/remote/path/file.txt /local/path/

This will download file.txt to your local machine.

Transfer entire directories

To copy a directory, use the -r (recursive) option:

scp -r directorio user@server:/remote/path/

Specify a different SSH port

If the server uses an SSH port other than the default (22), add -P followed by the port number:

scp -P 2222 file.txt user@server:/remote/path/

Transfer files directly between two remote servers

scp user1@server1:/remote/path/file.txt user2@server2:/remote/path/

# Conclusion

scp is a simple yet powerful tool for quick file transfers. If you’re looking for more flexibility or need to resume interrupted transfers, consider alternatives like rsync.