How to Use Math Department Computers

• Introduction
• Choosing a Password
• Disk Space
• E-mail
• SSH
• SFTP
• Xterm
• Remote Login
• LaTeX
• World Wide Web
• Creating your Homepage
• Common UNIX COMMANDS

Introduction

Choosing a Password

When you login to your Unix account for the first time, you should change your default password (command: passwd). In general you should change your password frquently. Unfortunately, the process of choosing a secure (non-guessable) password is not a trivial matter. It is complicated by the sophisticated technology available to system "crackers". The following list of DON'Ts are standard guidelines:

DON'T use:

a password with less than six characters.

a word in any dictionary (English or otherwise!)

a misspelling or reversal of a dictionary word. (i.e. "raazab", which is "bazaar" spelled backwards)

your name, your login name, or a trivial variation thereof (e.g. If your name is John P. Smith, and your login name is "smith", the following passwords would be considered guessable: "SMITH", "jsmith", "jp", "smitty", "sm!th", etc.).

any proper name of people or places

a sequence of keys on a typewriter ("qwerty") or in the alphabet ("abc123)

DO use:

a password that is the first letters of each of the words in a phrase

a password that includes one or more digits or punctuation symbols

both upper and lower-case letters

One well constructed password might be

"C!Wwbima?"

which came from the phrase, "Curious! Who would break into my account?", which uses all three of the above suggestions. This produces a random- seeming password that you can remember. Of course, now that it's printed here, this example is not a good choice to use as your password.

Disk Space

The department does not currently enforce strict disk space quotas for our researchers. However, please be aware that you are sharing space on a disk partition with many other users. We ask that you please do not use so much space that others on the partition are not able to get work done. We may ask from time to time that users with files they no longer need on the system back them up and remove them.

It is also possible for one person to accidentally use up all of the free space on a disk. This can happen when a program crashes and dumps a very large core file, for instance. By typing the command "limit coredumpsize 3m" at the prompt or as a line in your ".cshrc" file, coredumps would be limited, in the affected shells, to three megabytes in size. See "man csh" for details.

We also request that users try to run large or computationally intensive jobs only in off-peak hours, to keep machines usable during the day for interactive users. We also ask that you make sure your jobs exit normally so that other programs can use the memory after you are finished with it. If you have any problems or questions, please talk to the system administrators.

Using e-mail

Various sophisticated mail packages can be used .We support pine,Netscape Mailer,Thunderbird and Webmail.
http://math.asu.edu/mail
http://mathpost.asu.edu/mail

Check the appropriate man pages and the programs' own on-line help for more information.

SSH: Remote workstation access

To connect from one workstation to another,please use SSH. Math uses SSH2 protocol.

ssh "username"@"machinename"

or

ssh "machinename" -l "username"

For example,to connect to mathpost.asu.edu as user "smith",

ssh mathpost.asu.edu -l smith

or

ssh smith@mathpost.asu.edu

NOTE:If you connect to another workstation,the first time you might get an error message about the hostkey.The work around is to use debug mode,strace.

strace -o log ssh smith@mathpost.asu.edu

SFTP:Secure File Transfer Protocol

If you want to transfer files or directories from one workstation to another,please use SFTP or the graphical interface gftp.Please make sure that,in gftp,the transfer protocol is set to ssh2.

Terminal Window

It is advised to use xterm as the terminal window.Xterm is available under Linux,Unix and Mac OS.All Linux users should click on the redX at the toolbar.

Default setting for Math Computers :

xterm -ls -sb -sl 1000 -fn 10x20

Remote display

While using SSH2 protocol,the remote display is set automatically.

In some circumstances it might be necessary to set the display via the environment variable "DISPLAY".

You have to do the following 5 steps (step (iv) depends on your shell):

(i) Open terminal window(xterm)

(ii) allow remote access to your machine:

Xhost + "remote machine name"

(iii) ssh to remote machine

(iv) set display to local machine

Csh:    setenv DISPLAY "localmachine":0.0

Bash:   export DISPLAY "localmachine":0.0

(v) execute command

LaTeX

Running LaTeX

Most people use the graphical LaTex editor Kile(linux) , Winedt(Windows)

For Command line users:

The technical text formatting program LaTeX, including the previewer, is available on all workstations. All LaTeX source filenames must end with ".tex", for example "paper.tex". To run LaTeX on a source file named "paper.tex" type one of:

"latex paper.tex"

If there are no errors in your source file that prevent it from doing so, LaTeX will process your file and then halt, with an indication that it has created the device independent (".dvi") file named "paper.dvi". If there are such errors in your source file, LaTeX will point them out in sequence. Repeated use of the "<RETURN>" key will enable you to page through the list, after which TeX may create "paper.dvi" and "paper.log" (a file containing the list of errors in "paper.tex"), and then halt.

Unfortunately, LaTeX may stop processing before creating the ".dvi" file. Usually a "control-D" will halt the LaTeX program and return to the Unix prompt.

Once the file "paper.dvi" has been created, you can create a postscript (".ps") file directly by typing

"dvips paper.dvi"

To check the spelling in a LaTeX under Linux, type

"ispell paper.tex"

Previewing

Under X windows, you may preview either a ".dvi" file or a ".ps" file by typing:

"xdvi paper"

or

"gv paper.ps" or "kghostview paper.ps"

respectively. An advantage of previewing a ".ps" file is that figures are visible. Some newer implementations of xdvi may also display figures.

Printing

To print out your LaTeX document, print the ".ps" file by typing

"lpr paper.ps" or "lp paper.ps"

It is also important to know on which printer your file will be printed. For "mathpost" the default printer is located in GWC 607.

Using the World Wide Web

The World-Wide Web (WWW) is a hypertext-based interface to Internet services that includes most of the functionality of ftp and Gopher. It is strongly recommended to use

firefox

as your default webbrowser. Mac users can use Safari.

To create your homepage click here.

Common Unix Commands