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Solution Center - Main

Page history last edited by Qingqing Mao 9 years, 11 months ago

This site is a place to post questions about problems in your classes or research.  You can ask how to solve a certain kind of problem in planetary dynamics, or how to create a certain effect in an SM plot, or how to declare a variable in FORTRAN.  No question is too trivial or too broad, but the more specific you are the likelier you are to get an answer.  You can list your name with your question, or just post anonymously.


Post short pieces of information in the table below.  To contribute a solution, create a link in the table to a new wiki page where you can list a longer discussion.




Question Solution
Solution by



How do I read journal articles from home?

Prefix the url of the article with this: http://proxy.library.vanderbilt.edu/login?url=

You'll be redirected to the VU library to enter your userID and password.



What e-mail lists are there? E-mail lists     12/12/08
Does anyone know how to create symbolic links to directories in bash? ln -s   bash 2/13/09
How do I set up my laptop to print to the 9th floor Astro phaser (room 6913A)?

Download the drivers from the Xerox website.  Click on the first download link.  Follow the instructions.

See here for more directions from structbio (requires on-campus location). Make sure that you select the phaser6360 socket and not the default colorq (that one is located somewhere in MRB III). 

However, for Macintosh computers (haven't checked on Windows), the instructions given at structbio are confusing and possibly wrong.  Use these instructions instead.

  Windows/Mac OSX 3/9/09
How does one change the color of background and foreground for a document produced by LaTeX? For e.g. what if I want green text on a black background?

In the preamble of your LaTeX document, put \usepackage{color}.  Then to make the font a specific color, do:

\textcolor{color}{words to be in color}

For changing the background color, do \pagecolor{blue}.

  LaTeX 3/11/09

How do I set up my personal webpage?

How do I make files available to people outside of Vanderbilt?

set up your own web space




Mac OS X/ Windows

I'm lazy trying to be expedient in making unit conversions/looking up physical parameters of X, Y, Z objects.  Where can I find such things quickly?

WolframAlpha Astronomy page

Unit conversions example here

I use Thunderbird as my Vanderbilt email client, and I'm having problems with the disk space limit, or I'm receiving emails saying I am almost exceeding my quota limit and I don't know how to fix it. manage your email space
Josh Email 8/26/09
I'm having issues with IDL Direct Graphics- tvrd() or other device commands aren't working properly (e.g., image data stored in 2D arrays instead of 3D with R, G, B component).

Make sure IDL is in 8 or 24 bit mode.

VNC users beware, sessions start

up in 16 bit by default.  Use -depth 24 keyword when starting a VNC session.

  IDL, VNC 8/25/09
How do I use remote access to my estrella/vpac account?

First, set up your VPN to access the Vanderbilt network.  Then, use NX to make the connection to your computer.

Set up NX Client [updated]

Keivan All
I'm having IDL problems since switching to v7.1. I think it doesn't know where the idl astro library is. Can anyone tell me how to add the idlastro lib to the idl path? IDL7.1 lives on a different server that does not seem to have astrolib installed. The astrolib package just needs to be downloaded from here and copied to /net/vpac00/usr/local/idl/idl71/lib/. This needs to be done by someone with superuser permission, so this should be resolved by submitting a trouble ticket. (Keivan submitted the trouble ticket and this is now resolved.) Resolved by Keivan IDL 8/31/09
How do I set up an alias for my vanderbilt email address? How do I forward my vanderbilt email to another address? Sign in here and change your preferences: https://www2.vanderbilt.edu/vunet/modify.html   Email 9/21/09
How do I use sed for command-line modification of files? See this page for a list of cool tricks to do with sed. Mirrored here. Josh sed, shell 10/7/09
How do i view FITS images continuously (like in a slideshow)? For e.g. 'gs' allows you to do this with postscript images.

Use a simple IRAF script, posted here on the wiki and as a downloadable file here


There is also a very pretty Mac program that does this - QLFits - it does cost 2.95euro but there is a limited free demo you can try out.










How do I view a fits header within the shell, rather than within IRAF?  I want to view headers in full or specific fields. Use the fitshead and fitskey shell scripts.  Find them in the Software Repository here. Josh Shell 1/8/10
How do I measure the FWHM for a set of stars on an image? Use the kfwhm script.  Check in the Software Repository here for details. Josh C 1/13/10
Syntax highlighting in Emacs with Fortran 90 files (*.F90 files)

Add the line to your .emacs file:

(setq auto-mode-alist

        (cons '("\\.F90$" . f90-mode) auto-mode-alist))


Manodeep Linux, Fortran 1/18/10
What is an easy way to manage my BibTex database For those with Mac's, I suggest BibDesk. Otherwise, I suggest the Java program JabRef . If you have a Mac and have $42 to spare, Papers provides lots of bells-and-whistles.




OSX,Linux,Windows 1/26/10

How do I install a frontend for LaTeX in Linux?

For Ubuntu Linux users (as of Karmic Koala - 9.10), open a terminal, and type "sudo apt-get install texlive" to install the base LaTeX files. To then install the frontend, type "sudo apt-get install texmaker" to install TeXmaker. Now you can run TeXmaker by selecting from the menu: Application>Office>Texmaker.







How do I combine separate plots into one page?

for PS:

% psmerge plots*.ps | psnup -4 > out.ps

for PDF:

(i use a LaTeX package called pdfpages, see example on latex page)

discovered this functionality is included in the PDFjam package via pdfnup command, see


for PNG: (or any other bitmap image format)

% montage -tile 2x2 one.png two.png three.png four.png out.png
if you need to resize the output image, in case the default output 
image is too small or big, you can use "-geometry": 
% montage -tile 2x2 -geometry 800x600 1.png 2.png 3.png 4.png out.png
for PS/PDF:
gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile='' one.pdf two.pdf




*nix 1/28/2010
How do I kill processes by name (rather than process ID)

use the "killall"  command instead of "kill".  e.g.

% killall -9 xterms

Copying text from X11 to pasteboard in Snow Leopard

Select the text in xterm etc and then run 'echo "<pasted text>" | pbcopy '

(Alt-Click to paste into xterm)

Manodeep Mac  
What is GREP?  GREP is a unix command that helps you find substrings. See for this page for more information. brittany unix 02.08.2010
How do I use Regular Expressions? Here are some examples of how to use Regular Expressions with GREP. See this page for more information.  brittany unix 02.08.2010
How do I use footnotes in the LaTeX table environtment? Using \footnotemark and \footnotetext sometimes works, and sometimes I get footnote marks and no footnote.

You can use the package 'threeparttable', found here: http://www.tex.ac.uk/tex-archive/macros/latex/contrib/threeparttable.zip

Where can I find a list of empirical high resolution, high signal to noise stellar spectra?


The UVES Paranal Observatory Project

Field Stars Across the H-R diagram

How can I use the du command to list the sizes of directories and also display in human-readable format?

Put this text in your .myaliases file:


alias du1='du -h --max-depth=1 > dutemp; grep [0-9]G dutemp | sort -nr; grep [0-9]M dutemp | sort -nr; grep [0-9]K dutemp | sort -nr; rm -f dutemp'


That line will create an alias called du1.  It runs du with the -h option (display in human-readable format) and also only down a single directory level.  It pipes the output to a temporary file called dutemp, then uses grep and sort to display the lines from that file in the correct order, then deletes the temporary file.

Unix / Linux
How do I use GREP,SED or AWK? Here are the GREP, SED and AWK tutorials to help get you started. brittany unix 06.05.2010
Can AWK recognize user defined shell variables?

Yes. You can either use -v or extra quotations


ex. 1

$ PI = 3.14

$ awk -v val=$PI  '{print val*$1}' abc.dat

val is just a user defined variable. 




$ PI = 3.14

$ awk '{print ' "$PI" ' *$1} abc.dat

Need to make sure that you have single and double quotes around $PI


Both are equivalent

brittany unix 06.05.2010
How can I start an xgterm window running IRAF anywhere on my machine without having to be in the IRAF home directory?

See my solution at this link:


Start IRAF in another window 

Phill IRAF  
How do I make a table for aastex? 

Found this website that is handy for making tables with your data file that you have.


brittany latex  
Configure pine for the new vanderbilt email server

You will need to update the pine config (main menu -> setup -> config; or directly edit the .pinerc file if you have used pine before)




Roy/Manodeep *NIX  



Why are my references in LaTeX not working? All references to my tables/figures/etc. have the same number!

To be on the safe side, place all labels for referencing at the bottom of your figure/table/etc. construct. If placed in the beginning, for some reason the references were not being displayed correctly.







    \caption{Some caption}

    \label{my_label} <--- Place label here!!!



Then reference your figure/table/etc. in your LaTeX documents using \ref{my_label}























How can I figure out when my star/object is visible?

Totally awesome Mac program - iObserve - it has the capability of synching with SIMBAD even!  It will also take an input list of stars.

(free for now, most recent version works best with Snow Leopard)


Mac / Observing 09.08.2010
How do I view very large fits images in IRAF with DS9?

If you want to use the "disp" command in IRAF to view images in DS9, you might run into problems with very large images.  Specifically, if the images are too big (e.g. 4096 x 4096), you will only be able to see the central 512 x 512.  That can be easily fixed by placing the following line in your IRAF login.cl file and restarting IRAF:


set     stdimage        = imt4096




How can I display scientific notation in my document?

Use this line in your preamble (before the \begin{document} statement):

\providecommand{\e}[1]{\ensuremath{\times 10^{#1}}}


The above creates a custom command for \e that replaces any instance of "calculator" scientific notation within the document to the proper format using described template. To use, try something like:


The flux calibration used in this study for the R-band is 2.25\e{-9}.













How can I convert a fits table to an ASCII table? Use the table_extract.py script.  See the 20110419.html entry of Martin's Python tutorial for more information. Josh Python 5/13/11
How do I open a file with a .bz2 extension?

This is an option used with tarballs.  If you have a file file.tar.bz2, just use the j option in tar:

> tar xvjf file.tar.bz2

Josh (from Kelly) shell










How do I save my iWeb site files?

Saving your iWeb site files involves saving the Domain.sites or domain.sites2 file buried within you Mac directories. This is different from saving your individual html folders and files, as iWeb does not have the ability to import a site, html or otherwise.


However, making a backup of the Domain.site or Domain.sites2 file will ensure that your site remains editable in iWeb. Navigate to: 


     /Users/username/Library/Application Support/iWeb


where username is the name used for your home folder on your Mac (you can go to this folder directly by typing Shift+Command+G while in the Finder, and copy/paste the above directory into the search box). There should be a Domain.sites (for iWeb '06) or Domain.sites2 (for iWeb '08/'09). Simply backup this file, and restore to the same directory if you ever refresh your computer, and your site should be available for editing!

















iWeb (Mac OS X), html web authoring









How do I figure out what parts of my code are the most computationally expensive? Use Valgrind.      

How do I chop out and save one page from a multi-page ps file?

> psselect -p# input.ps output.ps

         where # is the page number to extract.

How do I view extragalactic objects and their environments? Use RAVEN (radial velocity defined galaxy environments) in NED: http://proto.ned.ipac.caltech.edu/help/galenv/.  Username: nedguest; password: AAS2013. Ben WWW 1/14/13
How to get involved in SDSS?

Please visit the following page for how to sign-up for SDSS related accounts. 

How to get involved in SDSS

Qingqing   8/28/14



Information about particular software issues are posted in the various repositories on the Software Repositories page.

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