Gosset banner


Computer Diagnostics

Answers to common questions, regarding batch jobs, html, latex, password, pdf, postscript, printers, sas, Splus, spss, stata, top, thesis, window managers, zip/uu.

Batch Jobs


Chmod stands for the kind of accessibility that other have to your files. It gives you a chance to protect your files against outside eyes.
For files:
Only I can read and write to it (text files, images):
chmod 600 file                       
Only I can read, write to, and run it (programs, scripts):
chmod 700 file                      
I can read/write, everyone can see it:
chmod 644 file                      
I can read/write, everyone can see it and run it:
chmod 755 file                      
Apply permission xxx to all files in the current directory:
chmod xxx *                         
For directories:
Only I can access files, use ``ls'' to list files in the directory and create files:
chmod 700 dir                      
Others can access files (according to individual file permissions above) and use ls to list files:
chmod 755 dir                      
Others can access files. A good mode for public_html directory and subdirectories:
chmod 711 dir                      
Applies mode xxx to a directory and recursively to all subdirectories. Generally not useful in this manner since files and directories generally require different permissions:
chmod -R xxx dir                   
Add "write" permission to file for me, the "user". (All the numeric permissions also have shorthands like this. See the man pages for more details).
chmod u+w file                     


To ``publish'' a latex file on your homepage:

(1) create a dvi file.
(2) type: ``dvipdfm myfile.dvi''
OR (but the following is a bit outdated and may not work as well).
(1) create a postscript file of your latex file by typing: ``dvips -o myfile.ps myfile'' (2) convert the postscript file into a pdf file by typing: ``ps2pdf myfile.ps myfile.pdf''


To write a letter in Latex, save the following file to your directory, letter.tex. The margins are set in such a way that if you would print on departmental letterhead paper, it would fit exactly.

If you try to print and the printer cuts part of your page off, then you are probably using the old ``documentstyle'' command on the first line of your latex document. Replace this by ``documentclass[11pt]{article}.'' For a simple set-up, save the file practice.tex in your directory and copy the first 10 lines.

To view your latex file on the computer, type
xdvi myfile.dvi&                     
(Available on Aitken:) To print 2 latex pages on 1 page, type
dvi2up myfile.dvi                    
To create a postscript file from your latex file, type
dvips -o myfile.ps myfile            

To ``publish'' a latex file on your homepage by converting it to a pdf file:

(1) create a dvi file.
(2) type: ``dvipdfm myfile.dvi''

To include a picture in your latex document, see the code in the following file: practice.tex.


To change your password, type:

and follow the instructions on the screen.


PDF is the common format of a lot of big text documents on the Web. If you have a PDF file (for instance, an article that you wrote), then you can put it on your homepage. People in the outside world are much more likely to have a PDF reader than a postscript reader.
To view a PDF file, type:
acroread myfile.pdf                  
To convert a postscript file into a PDF file, type:
ps2pdf myfile.ps myfile.pdf          

To ``publish'' a latex file on your homepage by converting it to a pdf file:

(1) create a dvi file.
(2) type: ``dvipdfm myfile.dvi''

PhD Dissertation Information

The University has a site that details the requirements of a PhD thesis. It also contains links to LaTeX macros that you should download so that your thesis will meet the style guidelines required by the University.


To convert a dvi file to a postscript file, type
dvips -o myfile.ps myfile             
To view a postscript file on your computer screen, type
ghostview myfile.ps                  
To print 2 pages on one page of a postscript file, type:
mpage -2 myfile.ps | lpr             
To print 4 pages on one page of a postscript file, type:
mpage -4 -a myfile.ps | lpr          


To view how many people are printing already on a particular printer, type: ``lpq'' or for a particular printer:
lpq -Peck8                           
To cancel your print job. (1) Log in on the same machine that you printed from. (2) View the number of the job that you want to cancel by the ``lpq'' command. (3) If your jobnumber is 375, then type ``lprm 375'', or for a particular printer:
lprm -Peck8 375                      
(Available on Aitken:) To print 2 pages on one page of a latex file, type:
dvi2up myfile.dvi                    
To print 2 pages on one page of any file, type:
mpage -2 myfile | lpr                
To print 4 pages on one page of any file, type:
mpage -4 -a myfile | lpr             



For anyone who is analyzing unbalanced designs in Splus, make sure to do this first: (1) Type inside Splus:
(2) this opens the pico editor in which you will have to type
   options(contrasts = c("contr.treatment", "contr.poly"))
This is IMPORTANT because the current defaults in Splus are nonsense.
If you want to test for Tukey 1df multiplicative interaction, I have written a little Splus program. The S-plus manual also provides a program, but I have reason to suspect that it is not correct.
An Splus algorithm to perform the Box-Cox analysis.
How to run a batch job in Splus: (1) create a file ``commands'', that contains your Splus commands, (2) type:
nohup Splus5 BATCH commands outfile  
Now you can log out and leave.




Typing ``top'' in a window, will give you a list of all the jobs that are running on that machine. You can check for instance if there is an old job of yours (often Netscape that got inadvertently killed) that is still running.
To kill an old job, (1) type ``top'' and check the number of your job, say, 375. (2) Kill this job by typing ``kill -9 375''.

Window managers

Do you want to get the most up to date window manager with spending no energy? Type:
defaultwm windowmaker                
and then type from now on (instead of ``X11'') the following command when you start your Xwindows:

Zip and Uu

In order to make a file more compact, the zip technique is useful. Say that you have a bunch of files in a directory and you want to compress them all:
gzip *                               
In order to get the files back again, just do:
gunzip *.gz                          
In order to send a couple of files by email, it is easiest first to compress them all to one archive file:
tar cvf archive.tar file1 file2 file3 ...
Then compress the archive file:
gzip archive.tar                     
Then create a uuencode file:
uuencode archive.tar.gz  > archive.uu 
Then send this file, archive.uu, via email.

To retrieve the original files, type (1) ``uudecode archive.uu'', (2) ``gunzip archive.tar.gz'' (3) ``tar xvf archive.tar''.

You can't find what you want? Go to the department computing page!