Remote Working

Linux, in common with other Unices, is network-oriented almost from the ground up. It is therefore natural to sit in front of one machine whilst using resources (diskspace, processing power,...) from several others.

To do this you can use standard Internet protocols such as telnet and ftp, but you can achieve much more if you know about the "r" commands and also about the X Windows system. (Other thin-clients are sometimes used too.)

The "r" Commands

In Unix, and in particular in Linux, there exist the so-called "r"-commands which facilitate interaction with other computers from the command line. These include:

rlogin

rlogin is similar to TELNET: it allows connections to remote machines.

rcp

rcp is a generalisation of the cp command which allows files to be copied between machines much more easily than by using FTP.

rsh

rsh starts a shell (command line) on a remote machine and therefore allows commands to be run on that machine without actually having to login.

rlogin can be used in a similar way to TELNET: simply type rlogin <remotemachine> and at the appropriate prompts type in your username and password.

To use the other "r"-commands you must create a file called .rhosts on the remote machine in your home directory --- you must of course have an account on the remote machine! An example: suppose user jim creates a .rhosts file

  flowerpot.umist.ac.uk bill
  flowerpot.umist.ac.uk ben
  garden.umist.ac.uk littleweed

The .rhosts file also obviates the need to type in the password when using rlogin. For example, if littleweed types

rlogin redneck -l jim

on garden she will be logged into redneck without further ado.

The "s" Commands

The "s" commands are, roughly speaking, functionally-equivalent to the "r" commands, except that they operate over a secure (encrypted) connection. However, authentication is considerably more sophisticated.

For details see the ISD document detailing Solaris and Linux security.

Thin Clients

There are several options for thin clients on Linux.

X Windows

...is the foremost solution. XFree86 Inc provide a (free) X-Server for unix-derivatives and for OS/2; there is even a port (using CygWin) to Windows 32.

Citrix

Citrix offer an alternative to X which started life as a thin client "solution" for MS Windows. This is a commercial product, though viewers/clients can be downloaded for free for just about anything including Linux.

VNC

I quote:

VNC stands for Virtual Network Computing. It is, in essence, a remote display system which allows you to view a computing 'desktop' environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures.

One can freely download VNC servers for Unix/X, Windows NT and the Apple Mac; VNC viewers for X, MS Windows, Java, Apple Macintosh, MS Windows CE. So, can't use X? Use VNC!

X-Windows

The X-window System is the standard graphical environment for most unix-like operating systems. Most windowing environments found in the unix world are based on the X Windows Protocol. X Windows most notable feature is that is supports running of processes on remote machines while the associated graphical display is shown on the local host.

• An introduction can be found within the Rute Users' Tutorial and Exposition (also at Source Forge).
  
  
• The home of the X Window System: X Org. Since its first commercial release in 1986, the X Window System has become one of the most successful consortium-developed open standards-based technologies...
  
  
• The XFree 86 Project, Inc. is a non-profit organisation that produces XFree86. XFree86 is a freely redistributable implementation of the X Window System that runs on UNIX(R) and UNIX-like operating systems (and OS/2, and even MS Windows).