February 28, 2017

How to Securely Transfer Files Between Servers with scp

scp-command.jpg

scp tutorial
This tutorial shows how to use scp (secure copy command), which encrypts transferred files.

If you run a live or home server, moving files between local machines or two remote machines is a basic requirement. There are many ways to achieve that. In this article, we talk about scp (secure copy command) that encrypts the transferred file and password so no one can snoop. With scp you don’t have to start an FTP session or log into the system.

The scp tool relies on SSH (Secure Shell) to transfer files, so all you need is the username and password for the source and target systems. Another advantage is that with SCP you can move files between two remote servers, from your local machine in addition to transferring data between local and remote machines. In that case you need usernames and passwords for both servers. Unlike Rsync, you don’t have to log into any of the servers to transfer data from one machine to another.

This tutorial is aimed at new Linux users, so I will keep things as simple as possible. Let’s get started.

Copy a single file from the local machine to a remote machine:

The scp command needs a source and destination to copy files from one location to another location. This is the pattern that we use:

scp localmachine/path_to_the_file username@server_ip:/path_to_remote_directory

In the following example I am copying a local file from my macOS system to my Linux server (Mac OS, being a UNIX operating system has native support for all UNIX/Linux tools).

scp /Volumes/MacDrive/Distros/fedora.iso 
swapnil@10.0.0.75:/media/prim_5/media_server/

Here, ‘swapnil’ is the user on the server and 10.0.0.75 is the server IP. It will ask you to provide the password for that user, and then copy the file securely.

I can do the same from my local Linux machine:

scp /home/swapnil/Downloads/fedora.iso swapnil@10.0.0.75:/media/prim_5/media_server/

If you are running Windows 10, then you can use Ubuntu bash on Windows to copy files from the Windows system to Linux server:

scp /mnt/c/Users/swapnil/Downloads/fedora.iso swapnil@10.0.0.75:/media/prim_5/
  media_server/

Copy a local directory to a remote server:

If you want to copy the entire local directory to the server, then you can add the -r flag to the command:

scp -r localmachine/path_to_the_directory username@server_ip:/path_to_remote_directory/

Make sure that the source directory doesn’t have a forward slash at the end of the path, at the same time the destination path *must* have a forward slash.

Copy all files in a local directory to a remote directory

What if you only want to copy all the files inside a local directory to a remote directory? It’s simply, just add a forward slash and * at the end of source directory and give the path of destination directory. Don’t forget to add the -r flag to the command:

scp -r localmachine/path_to_the_directory/* username@server_ip:/path_to_remote_directory/

Copying files from remote server to local machine

If you want to make a copy of a single file, a directory or all files on the server to the local machine, just follow the same example above, just exchange the place of source and destination.

Copy a single file:

scp username@server_ip:/path_to_remote_directory local_machine/path_to_the_file 

Copy a remote directory to a local machine:

scp -r username@server_ip:/path_to_remote_directory local-machine/path_to_the_directory/

Make sure that the source directory doesn’t have a forward slash at the end of the path, at the same time the destination path *must* have a forward slash.

Copy all files in a remote directory to a local directory:

scp -r username@server_ip:/path_to_remote_directory/* local-machine/path_to_the_directory/ 

Copy files from one directory of the same server to another directory securely from local machine

Usually I ssh into that machine and then use rsync command to perform the job, but with SCP, I can do it easily without having to log into the remote server.

Copy a single file:

scp username@server_ip:/path_to_the_remote_file username@server_ip:/
  path_to_destination_directory/

Copy a directory from one location on remote server to different location on the same server:

scp username@server_ip:/path_to_the_remote_file username@server_ip:/
  path_to_destination_directory/

Copy all files in a remote directory to a local directory

scp -r username@server_ip:/path_to_source_directory/* usdername@server_ip:/
  path_to_the_destination_directory/ 

Copy files from one remote server to another remote server from a local machine

Currently I have to ssh into one server in order to use rsync command to copy files to another server. I can use SCP command to move files between two remote servers:

Usually I ssh into that machine and then use rsync command to perform the job, but with SCP, I can do it easily without having to log into the remote server.

Copy a single file:

scp username@server1_ip:/path_to_the_remote_file username@server2_ip:/
  path_to_destination_directory/

Copy a directory from one location on a remote server to different location on the same server:

scp username@server1_ip:/path_to_the_remote_file username@server2_ip:/
  path_to_destination_directory/

Copy all files in a remote directory to a local directory

scp -r username@server1_ip:/path_to_source_directory/* username@server2_ip:/
  path_to_the_destination_directory/ 

Conclusion

As you can see, once you understand how things work, it will be quite easy to move your files around. That’s what Linux is all about, just invest your time in understanding some basics, then it’s a breeze!

Learn more about Linux through the free "Introduction to Linux" course from The Linux Foundation and edX.

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