scp (secure copy) is a command-line tool for copying files between machines over SSH.
It uses the same authentication and encryption as ssh, so no extra setup is needed beyond SSH access.
Basic Syntax#
The general syntax of scp is:
scp [options] source destinationEither source or destination (or both) can be remote.
A remote path is written as:
user@host:/path/to/fileIf user@ is omitted, the current local user is assumed.
Copy a local file to a remote machine#
scp /path/to/local/file.txt user@remote_host:/path/to/remote/directory/If the destination is a directory, the file is copied into it. If the destination file name does not exist, it will be created. If it exists, it is overwritten without warning.
Copy a file from a remote server to local#
scp user@remote_host:/path/to/remote/file.txt /path/to/local/directory/If the local target is a directory, the original file name is preserved.
Copy directories recursively#
By default, scp only copies files. To copy directories, use the -r option:
scp -r results/ user@remote_host:/path/to/remote/directory/Specify a different SSH port#
If the remote SSH server listens on a non-standard port (not 22), use the -P (uppercase) option to specify the port:
scp -P 2222 /path/to/local/file.txt user@remote_host:/path/to/remote/directory/This is different from ssh, which uses -p (lowercase) for specifying the port.
Mixing them up is a common mistake.
Use an identity file (private key)#
If you do not want to use the default SSH key, you can specify an identity file with the -i option:
scp -i /path/to/private_key.pem /path/to/local/file.txt user@remote_host
:/path/to/remote/directory/This is useful when managing multiple servers with different keys.
Preserve file timestamps and modes#
To preserve the original file timestamps and modes (permissions), use the -p option:
scp -p /path/to/local/file.txt user@remote_host:/path/to/remote/directory/This matters when timestamps are important, e.g., for backup or synchronization.
Limit bandwidth usage#
To avoid saturating the network, you can limit the bandwidth used by scp with the -l option (in Kbps):
scp -l 500 /path/to/local/file.txt user@remote_host:/path/to/remote/directory/This can help when running transfers on a shared network.
Verbose output for debugging#
If something fails or hangs, add -v (or -vv, -vvv) to see detailed SSH output:
scp -v /path/to/local/file.txt user@remote_host:/path/to/remote/directory/This helps diagnose authentication, key and connection issues.
When not to use scp#
For large directory trees or repeated synchronization, rsync is often better.
It supports incremental transfer, resume, and better progress reporting.
scp is most suitable for simple, direct copies.