Master Secure Copy (scp): Syntax, Options, and Real-World Examples

Introduction

The scp command stands for Secure Copy, combining the functionality of cp with SSH. It uses the SSH protocol (default port 22) to log into a remote host before copying files, ensuring both file data and passwords are encrypted during transfer. scp supports three copy modes:

Copy from local to remote.

Copy from remote to local.

Copy between two remote systems.

Basic Syntax

The syntax mirrors that of cp:

$ scp source destination

source

denotes the file’s current location, and destination is where the file should be copied. Both can include a username and hostname, separated by a colon. $ scp user@host:foo.txt bar.txt When a username or hostname is omitted, the current local user and host are assumed. scp also respects SSH client configuration in .ssh/config, allowing host aliases. scp can copy multiple files in one command: $ scp source1 source2 destination Be aware that existing files at the destination will be overwritten without warning.

Usage Examples

(1) Local to Remote

# syntax
$ scp SourceFile user@host:directory/TargetFile

# example
$ scp file.txt [email protected]:/remote/directory

Copy an entire directory recursively:

# copy local "documents" directory to remote, creating the directory there
$ scp -r documents username@server_ip:/path_to_remote_directory

# copy the whole local directory to a remote directory
$ scp -r localmachine/path_to_the_directory username@server_ip:/path_to_remote_directory/

# copy all contents of a local directory to a remote directory
$ scp -r localmachine/path_to_the_directory/* username@server_ip:/path_to_remote_directory/

(2) Remote to Local

# syntax
$ scp user@host:directory/SourceFile TargetFile

# example
$ scp [email protected]:/remote/file.txt /local/directory

Copy a remote directory recursively:

# copy a remote directory to a local path
$ scp -r username@server_ip:/path_to_remote_directory local-machine/path_to_the_directory/

# copy all contents of a remote directory to a local path
$ scp -r username@server_ip:/path_to_remote_directory/* local-machine/path_to_the_directory/
$ scp -r user@host:directory/SourceFolder TargetFolder

(3) Remote to Remote

# syntax
$ scp user@host1:directory/SourceFile user@host2:directory/SourceFile

# example
$ scp [email protected]:/files/file.txt [email protected]:/files

The command will prompt for passwords of both remote accounts and transfer data directly between the two remote hosts.

Configuration Options

-c cipher : Specify the encryption algorithm for data transfer.

$ scp -c blowfish some_file [email protected]:~

-C : Enable compression during transfer.

$ scp -c blowfish -C local_file [email protected]:~

-F ssh_config : Use a specific SSH configuration file.

$ scp -F /home/pungki/proxy_ssh_config Label.pdf [email protected]:/root

-i identity_file : Specify a private key for authentication.

$ scp -vCq -i private_key.pem ~/test.txt [email protected]:/some/path/test.txt

-l limit : Limit bandwidth (Kbit/sec). Example limits to 80 Kbit/s (~10 KB/s).

$ scp -l 80 yourusername@yourserver:/home/yourusername/* .

-p : Preserve modification time, access time, and mode.

$ scp -p ~/test.txt [email protected]:/some/path/test.txt

-P port : Specify the remote SSH port (useful when not 22).

$ scp -P 2222 user@host:directory/SourceFile TargetFile

-q : Suppress progress meter. $ scp -q Label.pdf [email protected]:. -r : Recursively copy directories.

-v : Verbose output for debugging.

$ scp -v ~/test.txt [email protected]:/root/help2356.txt