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Using Linux

Can I bring in my own Linux PC and use it on the Math Department network?

Yes, but with the following stipulations:

  1. We must install a fresh copy of Fedora on the machine
  2. We will have the root password and will not turn it over to you
  3. We will maintain the machine just as we maintain all machines on our network presently

Why do I get a "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!" message when trying to use SSH?

You will see this scary looking message if the host key of the server you are attempting to ssh into does not match the host key your local computer remembers it to be. This could mean that the server has been re-installed, or that the host key has been changed for security purposes. This could also mean that someone could be eavesdropping (man-in-the-middle attack) while you are attempting to establish a connection, so it is generally a good idea to contact the department help desk (help@math.mit.edu) to double check that we did change the host key. Otherwise, you can override this warning by issuing this command:

ssh-keygen -R hostname

Where 'hostname' should be the name of the server your are attempting to connect to. When you next try to connect to this server, you will be prompted to download the new host key.

Can I bring in my laptop running Linux and use it on the network?

Yes, if it registered on the MITnet network. To register your laptop, connect it to the wired network, wait for it to establish a connection, then open up a web browser. If your laptop is not yet registered, your web browser will be directed to MTI web page where you can enter your information (including athena username/password info). You can also register it as a guest to have access for a limited time period.

Can I have a dual boot of Windows and Linux if you install Redhat for me?

No. Other solutions are available for your Windows needs.

What about Linux on Non i386 Platforms?

Support is available for AMD and Intel 64-bit CPUs.  Linux on any other platform (Mac, sparc, alpha, etc.) will not be supported at this time.

Will you help me buy a new Linux PC for my office?

Yes. If you have a grant or want to buy a PC with your own money please consult with us and we will help you choose the best system for you and install it as well.

What is the supported desktop environment/window manager?

The default window desktop environment/window manager is GNOME.

Other window managers, including KDE, are available for you to use if you choose. Please understand that support will only be offered for GNOME.

How do I convert a .dvi file to a .ps?

Use dvips:

dvips -ooutput.ps input.dvi dvips -omathematics.ps mathematics.dvi

Make sure there is no space between the -o and the output filename.  If you only need a few pages converted, use the following commands:

dvips -pstartpage -lendpage -ooutput.ps input.dvi dvips -p3 -l12 -omathemathics.ps mathematics.dvi

How do I tar and zip my files so I can transfer them all at once?

The easiest thing to do is to put all the files you want to transfer in a single directory. Once all files are in the directory type:

tar zcvf dirname.tgz dirname

You will now have the file dirname.tgz

When the file is transferred to its new home, type:

tar zxvf dirname.tgz

The directory will now be in place with all files in it.

How do I keep a process running after I have logged out?

Use the screen command. Here is a brief tutorial:

  1. At a terminal, before starting your proccess, type screen. You are now within the "screen".
  2. Begin any proccesses you would like to stay running after logging out.
  3. To detach from the "screen", hold down the Control key and type a then d. You are now detached from the screen and can log out. To see a list of your running screens, type screen -ls.
  4. Before you can re-attach to your screen, you will need the name of your screen. To get this, type screen -ls. You will see a list of one or more screen which look something like 27940.pts-12.runge.
  5. To re-attach to your screen, type screen -r screen_name, where screen_name is the name of your screen.

See the screen manual for more details.

How do I set the priority of my compute job to be nice?

The following are guidelines for running compute jobs that are cpu and/or memory intensive.

A key point when using those machines is that whenever you submit a compute job (including Matlab, Mathematica, Splus or Maple) that will run in the background for more than about 2 hours, you should politely assign it the LOWEST priority possible. You can do this easily by prefixing nice +19 at the time of submission, as in:

lagrange~::> nice +19 myspecialjob &

Also, you can subsequently lower the priority of one of your jobs that is already running via the command: renice -n 19 -p 12345 if its PID (program ID) happens to be 12345.

This will ensure that those who need a short interactive session with Matlab, Mathematica, etc. can do so quickly, without your background job getting too much in their way.

Please note: One serious problem with Matlab is if you logout or are logged out without exiting the program, it will sometimes continue running, often at a high priority. So once you are done, check with ps auxw | grep matlab for a runaway process. If you find that it is still running, please kill it at once.

How do I use a CD-Rom or USB drive in Linux?

Insert your CD-Rom or USB key. Double Click the Computer icon on the GNOME desktop. In the Computer window that opens, double click on the appropriate icon (CD or USB Drive). A window representing the contents of the removable device you have inserted will open and an icon for that device will appear on the desktop. You can now double click on your Home icon and drag and drop files. When you are done using the device, right click on the removable device icon (CD or USB Drive) on the desktop and select unmount. Your CD will eject and/or you can manually remove your USB drive.

How do I open a Microsoft Office document?

OpenOffice is installed on all Linux workstations. If you use the View Attachments feature in Pine, OpenOffice will automatically open Word, Excel and PowerPoint documents.  Also, OpenOffice will open automatically when you double-click any Microsoft Office document in your Home folder. To use the command line, type ooffice and the name of the document.

How can I find out about new software installed or updates to current software?

If you would like to receive an email when software packages are installed or updated, please send an email to help@math.mit.edu.  Just type Software Update List in the subject line.