Transfer Data#

  • Upload, Download, & Extras

Transferring Files/Folders Remotely#

Previously, we learned the linux commmands, cp and mv, to manage files locally in the terminal.

To copy files through ssh, we need to use one of two commands:

  1. rsync remote (and local) copy

  2. scp - secure copy

The format for them are:

rsync /path/to/source/ /path/to/destination
scp /path/to/source /path/to/destination/

Both require a source (original file) as the first option, followed by the destination (where you want the copy). This is similar to the syntax of cp and mv. The biggest difference is that you will need to include your HPC account:

Example If you’re copying a local file, to Oscer, it would be:

scp /path/to/local/source username@schooner.oscer.ou.edu:/path/to/destination

Copying the local file to Oscer with scp needs username@hostname: followed by the absolute path to the destination. Note the :

I recommend using rsync because this will check files sizes and modify timestamps of both files or folders. It will skip any further processing if they match. Additionally, if the destination file already exists, the transfer algorithm will make sure only differences between the files are sent over the wire.

I won’t go further here, but you can find more information about rsync and scp later.


One last thing about ssh is that, you can also run commands without going through the whole process of logging in.

Command Execution with ssh#

What if the only thing you need to do over the SSH connection is execute a single quick command? You might not want to take the separate actions of connecting and authenticating, running the command, and then disconnecting. The ssh command allows us to execute command on remote machine without logging into that machine. Here is the general notation:

ssh van@pete.hpc.okstate.edu [COMMAND]

Where [COMMAND] is some bash commands.

Here is an example of making a new directory, test, without logging in:

ssh van@pete.hpc.okstate.edu mkdir -p test

Log into the supercomputer, and list the contents of your home directory. You should see that you have a new test/ directory.