SSH or Secure Socket Shell is a protocol that allows a secure way to access remote computer. SSH implementation comes with scp utility for remote file transfer that utilises SSH protocol. Other applications such as sftp and rsync can also make use of SSH to secure its network transaction.

All these applications allow us to copy our local files to remote server and to copy files from remote server to our local machine. Below are examples on how to use these applications for files transfers based on this setup:

The easiest of these are scp or secure copy. While cp is for copying local files, scp is for remote file transfer. The main difference is that with scp you'll have to specify the remote host's DNS name or IP address and provide login credential for the command to work.

1. Copy single file from local to remote.

   $ scp myfile.txt remoteuser@remoteserver:/remote/folder/

2. Copy single file from remote to local.

   $ scp remoteuser@remoteserver:/remote/folder/myfile.txt  myfile.txt

3. Copy multiple files from local to remote.

   $ scp myfile.txt myfile2.txt remoteuser@remoteserver:/remote/folder/

4. Copy all files from local to remote.

   $ scp * remoteuser@remoteserver:/remote/folder/

5. Copy all files and folders recursively from local to remote.

   $ scp -r * remoteuser@remoteserver:/remote/folder/

remoteuser need to exist and have write permission to /remote/folder/ in the remote system.

sftp or Secure FTP in the other hand works almost exactly like ftp but with secure connection. Most of the commands are similar and can be used interchangeably. The following sftp example will work exactly as ftp would.

$ sftp user@192.168.1.10
Connected to 192.168.1.10.
sftp> dir
file1      file2  file3   
sftp> pwd
Remote working directory: /home/user
sftp> get file2
Fetching /home/user/file2 to file2
/home/user/file2                                                   100% 3740KB 747.9KB/s   00:05    
sftp> bye
$ 

You can also use ssh to secure your rsync session. To do this, use --rsh=ssh or -e “ssh” with your normal rsync commands. The following 2 commands will work exactly the same;

$ rsync -av --delete --rsh=ssh /path/to/source remoteuser@192.168.1.10:/remote/folder/
$ rsync -av --delete -e "ssh" /path/to/source remoteuser@192.168.1.10:/remote/folder/

If these options are not specified, rsync will first try to connect to rsyncd but will automatically fallback to SSH if rsyncd is not running in the remote system.