Duke University
Center for the Study of Aging and Human Development

Computing & Statistics Lab

Chapter 8 Inter-Networking - Computers of the World at Your Finger Tips

     The following programs and commands run on the geri system, as
opposed to those programs discussed in chapter 2, which run on a pc. If
you already have Netscape and ssh on your pc, there is no reason to log
on to the geri system. However, if you wish to transfer files from the
geri system to another UNIX computer, you must first establish an
interactive session on the geri system and run sftp or ftp.

Netscape -

     You can run Netscape from the geri system as long as you are running
an X Windows emulator on your pc (see Chapter 2). To do so enter the
command 'netscape &' at the UNIX prompt in your terminal window. The '&'
symbol tells the system to run the program in the background so you can
continue to do other work in the same terminal window.

SSH -

     SSH stands for Secure Shell and is preferred over telnet because it
encrypts your data as it travels over the network. Both programs allow you
to establish interactive sessions on other UNIX computers for running
programs on the remote computer. To establish such a session enter the
command 'ssh host.domain.net'. For example, to work on the acpub computer
called godzilla you would issue the command 'ssh godzilla.acpub.duke.edu'
and log on with your username and password. If you get a message saying
you are using an incorrect ssh protocol, try 'ssh1' instead of 'ssh'.

sftp -

     'sftp' stands for 'secure file transfer protocol.' All you can do
with this program is transfer files from one computer to another. If you
need to edit that file or run a program on the remote computer that uses
that file, you will need to use ssh or telnet to establish an interactive
session. What makes this ftp secure is that all of your data is encrypted
before being sent over the network.

     If, for example, you wish to transfer a file to the acpub computer
godzilla, you would issue the command 'sftp godzilla.duke.edu username',
where 'username' is your login id on the remote computer. When you are
logged in you will see the 'ftp>' prompt at which point you can issue the
appropriate ftp commands. 'help' is always a good one to start with, but
the most common are - 'ls' to get a listing of the directory on the
remote computer; 'cd' to change directory on the remote computer; 'put' to
transfer a file from the local to the remote computer; and 'get' to
transfer a file from the remote computer to the local computer.