The Maths Unix System

From Mathsoc wiki

The School of Maths run a Unix Komputer system (Salmon, Walton, Gosset etc.), alongside a Debian Linux system (Turing, Graves, Stokes, Graham). What follows is mostly useless information collected by people with too much spare time on their fingers.

Contents 1 The hosts 1.1 FreeBSD hosts 1.2 Debian hosts 1.3 Other hosts 2 Useful commands 2.1 Moving around and file operations 2.2 Stalking people 2.3 Miscellaneous 3 Access from home 4 Miscellaneous 5 Fun things to do when someone forgets to logout 6 Further links

The hosts

When logging in from the maths computer rooms you have to choose a host from a screen with a load of names and pictures of people. These are named after mathematicians/physicists/computer scientists. The smiley faces show how much load each host is carrying - the smilier the face the better it is to use.

FreeBSD hosts

These aren't very nice to use (with the exception of jbell), but most people don't realise there's a better alternative. Open a terminal by clicking the shell icon, type firefox to run Firefox 1.5. Or else use Konqueror...

• salmon
• synge
• hamilton
• walton
• gosset Hosts the mysql server
• boole
• astro
• bell
• jbell Updated with Firefox 3, but DEATHLY SLOW.
• graham Also updated but DEATHLY SLOW,

Debian hosts

These once were better hosts and maybe still are, the web browser is Iceweasel 2 (which is Firefox 2 in all but name). You can even change your desktop environment prior to logging in.

• graves Very few people seem to use this.
• turing Gnome works on this, but you have to enter your password when sshing anywhere which is annoying.
• stokes
• gstokes Supports ssh -X.

Other hosts

• lanczos Not listed as a login, this is better in some technical way for sshing and is reserved for staff or students who have a good reason to use it, as far as I know.
• mysql There is also a mysql server, for mysql (a database thingy).

Useful commands

Moving around and file operations

• cd: Changes directory; entered without specification brings you back to home directory.
• cd ..: move up a directory
• pwd: Prints current directory path
• ssh: login to a different host
• ls: lists all files and folders in a directory.
• touch: creates a file
• rm: removes a file
• mkdir: makes a directory
• rmdir: removes a directory (must be empty)
• chmod: Changes permissions; otherwise people can look inside your home directory at all your files! Good thing we all have so much respect for privacy, eh?

Stalking people

• finger: tells you everyone who's logged in, finger username gives the last the time that user was seen, finger -l username gives more information.
• w: tells you who's logged into your host and what they're doing

Miscellaneous

• yes [word(s)]: Produces an infinite output of "word(s)". Amazing.
• top: lists currently running process
• <ctrl>+<alt>+<L>: instant lock screen
• <ctrl>+<alt>+<backspace>: instant logout

Access from home

You need to use SSH to access from home:

• For Windows, you can use putty or SSH Secure Shell, available from the IS Services site (need to be using the TCD proxy http://www.tcd.ie/proxy.cgi to get access I believe. And even then it seemingly still isn't accessible or something).
• Windows users can also use WinSCP to access their home directory from anywhere. Just use maths.tcd.ie as the host and login with the username and password you use for the Maths Unix system.
• Mac OS X users may use built in ssh program via the terminal called 'terminal'.
• NIX users may use the terminal called 'Konsole'/'Xterm' to access ssh.

• Most modern linux distros should allow you to type "ssh -fX username@salmon.maths.tcd.ie xterm" into a terminal to pop up an xterm from the maths computers. From there, gui programs, such as gedit, can be run from the maths computers. Very handy for editing files for your site.

• Users of iPhones/iPods/etc. can SSH into the maths servers by first jailbreaking their device, then installing "MobileTerminal" (or some other terminal app) and "OpenSSH" from Cydia.

• If this confuses you, you can also just use the Maths Java client, which just requires that you have the Java client installed.

Once you have a terminal open, simply type in "ssh [username]@[host.]maths.tcd.ie" when prompted, enter your password and Voila!

Miscellaneous

• Deleting 170,000 small files causes the fileserver (maccullagh) to break. Avoid doing this.
• The Maths website was one of the first 100 in the world, being created in 1993.
• You can amuse yourself by browsing the mailing list archives or the www logfiles, or even the Wayback Machine archive, which yields such gems as a collection of Yeats' poetry and an Anne Rice fan site.
• For some reason the Maths servers host both a collection of guitar tabs, and an archive of information, pictures and weird short stories related to Gothic music. You can find them at http://www.maths.tcd.ie/local/JUNK/music/ (or in /archive/pub/music if you're logged in).
• Some simple cgi scripts can be found at /www/common-cgi; again, you must be logged on.
• The printers are laser14 or laser19-11, or else wr14 and wr19-11, which depends on your host and trial and error is needed to ascertain how to actually print anything. Duplex by default!
• There is also a kettle. (it is gone for some reason:( )

Fun things to do when someone forgets to logout

1. Run the command chmod 777 ~/www/index.html
2. Be inventive and compose an interesting email to be sent to msgs and mailing lists.
3. Run the command chmod 777 *.* while in the home directory
4. Add a command to .login to run a program which produces an infinite loop of printf("Don't forget to log-out, Fool!"); Alternatively add the command logout to the .login file

Further links

• Dave McConnell's 061 page
• The incomplete 061 course
• Netsoc's senior admin's guides - It should be noted that this is for a Solaris system though and so varies in helpfulness.
• Richard Timoney's Introduction to the maths system
• Richard Timoney's Introduction to Mathematica
• Linux reference card