Logging On Tutorial for Linux and Mac Users

Logging On and Transferring Files for Linux and Mac users

winscp Users of VPAC's High Performance Systems generally connect to VPAC from their own computers within their University (or, perhaps from home). Most such connections are based on the ssh (secure shell) protocol and tools to provide a "terminal session" and to transfer files. Please see the pages below for your operating system of choice, it will tell you about what tools we recommend and how to get them working. VPAC does not allow protocols such as Telnet, FTP or RSH as they insecurely send plain-text passwords over the network.

Windows Users
Please see our Logging on with Windows

Mac and Linux users
Linux distributions almost always include SSH as part of the default installation as does Mac OS 10.x, although you may also wish to use the Fugu SSH client. This discussion is primarily about command line access, if you need to establish a GUI session with a VPAC system, you need to use XWindows.

If using Mac OS 10.x, you will probably want to add a terminal alias to your dock. From the Macintosh HDD and go to the Applications folder, then Utilities from within that. Terminal is in the Utilities folder. Drag it to an empty space in the Dock, and the operating system will put an alias there. If you are using a graphic interface for Linux, like GNOME or KDE, you may wish to do the same with one of the terminal clients and panels.

To connect, simply open the terminal client and enter your username and the machine you wish to connect to, followed by the password when connected. For example;
ssh [your username]@trifid.vpac.org

To move files to and from the supercomputer and one's desktop you need to use an SCP (secure copy protocol) or SFTP (secure file transfer protocol) over SSh. You will be able to do this with the standard command-line interface with the general procedure of;

scp account@source.address:/path/to/file account@destination.address:/path/to/file

File transfer examples

  1. Here is an example for someone who's username is jsmith, he is getting a file called myfile.data that in a directory mydir, off his home directory on a VPAC ,machine :
    scp jsmith@trifid .vpac.org: . Note the dot at the end of that command line, scp will complain if you forget it !
  2. Here is another example, the same user wants to copy another file, myfile_2.data from his desktop to the same working directory at VPAC :
    scp myfile_2.data jsmith@trifid .vpac.org:
  3. "Putting" an entire directory
    scp -r datadirectory username@trifid .vpac.org:datadirectory/
    This is a recursive "put"; it will copy over the entire directory and any subdirectories.
  4. "Getting" an entire directory
    scp -r username@trifid .vpac.org:/datadirectory ./datadirectory/

There is also a handy program called rysnc which provides an incremental secure file transfer. In other words, it only replaces those parts of your files on your destination machine when they have been modified on the source machine. This makes transfers of large numbers of files a great deal faster.

rsync -a -e ssh source/ username@trifid .vpac.org:/home/user/destination/

This would move all files from the folder 'source/' to the folder 'destination/' on a remote machine, ensuring you have acopy of the two directories. The files are transferred in -a "archive" mode, which ensures that symbolic links, devices, attributes, permissions, ownerships etc, are preserved in the transfer. Be careful with those trailing slashes on the source argument - leaving it out will create an additional subdiretory underneath that specified on the destination. Finally, the command uses ssh (-e ssh) to determine the protocol that rsync uses to make the connections.

More information on OpenSSh and the latest version can be found at:

A tutorial on using rsync as a backup tool

Rsync for MS-Windows

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