What is Secure Copy?
scp allows files to be copied to, from, or between different hosts. It uses ssh for data transfer and provides the same authentication and same level of security as ssh. Which means it is much more secure than ftp. If possible all transfer should be done over scp.
Examples
Copy the file “helloworld.tar” from a remote host to the local host
$ scp username@remotehost.com:helloworld.tar /transfer/to/local/directory
Copy the file “helloworld.tar” from the local host to a remote host
$ scp helloworld.tar username@remotehost.com:/transfer/to/remote/directory
Copy the directory “foo” from the local host to a remote host’s directory “bar”
$ scp -r foo username@remotehost.com:/transfer/to/remote/directory/bar
Copy the file “helloworld.tar” from remote host “server1.com” to remote host “server2.com”
$ scp username@server1.com:/transfer/to/remote/directory/helloworld.tar \
username@server2.com:/transfer/to/remote/directory/
Copying multiple files “foo.txt” and “bar.txt” from the local host to your home directory on the remote host
$ scp foo.txt bar.txt username@remotehost.com:~
Copy multiple files from the remote host to your current directory on the local host
$ scp username@remotehost.com:~/\{foo.txt,bar.txt\} .
Improve SCP Performance
By default scp uses the Triple-DES cipher to encrypt the data being sent. Using the Blowfish cipher has been shown to increase speed. This can be done by using option -c blowfish in the command line.
$ scp -c blowfish some_file username@remotehost.com:~
It is often suggested that the -C option for compression should also be used to increase speed. The effect of compression, however, will only significantly increase speed if your connection is very slow. Otherwise it may just be adding extra burden to the CPU. An example of using blowfish and compression:
$ scp -c blowfish -C local_file username@remotehost.com:~