• What software is in the CS Windows image?
• How do I create a Subversion repository for a code project?
• How do I use CSSD's VPN to access computing resources in the department?
• What are the configurations of the public printers?
• How do I configure my Windows 7 machine to print?
• How do I configure my Macintosh to print?
• My Pitt ID will not open the doors!
• I need access to the copy machine!
• I need to borrow a projector, a laptop or the conference phone!

1. Which machines can I use?
2. How do I connect to the CS UNIX servers?
3. Which printers can I use?
4. What is appropriate use of the printers?
5. How do I send files to the printers?
6. How do I send pdf files to the printers?
7. Where are the departmental photocopiers?
8. How can I access the wireless network in Sennott Square?
9. How can I get information about the video conferencing room in Sennott Square?
10. What are the configurations of the public printers?
11. How do I configure my Windows 7 machine to print?
12. How do I configure my Macintosh to print?

1. Why can't my directory under public/html be seen anymore (it used to work)?
2. How do I change my password?
3. How do I check my e-mail?
4. What is my e-mail return address?
5. How do I read my e-mail from home?
6. What is the URL for my home page?
7. What kinds of programs are there on the CS machines?
8. What information is available online?
9. How do I logout?
10. What do I do if I suspect I am having a hardware or software problem?
11. How do I set up my UNIX account to use LaTeX?
12. How do I set up my UNIX account to run other software in the Department?
13. How do I set up my Windows machine at home to be able to access AFS files?
14. How do I verify if the message I got about a virus is true or not?
15. Why do I sometimes get 2 requests for passwords when logging into Linux?
16. How can I look and edit MS Office (Word, Excel, etc) files in the UNIX machines?
17. How can I add to my $PATH variable?
18. How can I install programs (for everyone to use and not using my own disk quota) in the UNIX machines?
19. How do I create a symbolic link in UNIX?
20. How to have email forwarded to another address?
21. As an Instructor, I want to limit the network access during the classes I teach. What can I do?
22. Ruby on Rails
23. CSSD's Faculty Computing Program
24. What software is in the CS Windows image?
25. How do I create a Subversion repository for a code project?
26. How do I use CSSD's VPN to access computing resources in the department?

1. What do I do if I need more disk space?
2. How are my files set up?
3. How do I control access to my AFS files?
4. How do I set recursive permissions on AFS?
5. How often are my files backed up?
6. When I do an "ls -l" on the '/afs' directory my terminal hangs. Why?
7. How do I access other AFS cells?
8. I frequently have problems accessing files after I have been logged in for a long time. Why?
9. How do I clean up my account to get more space (core files specifically)?

Other Important Topics

1. What do I do if the pipes are leaking, the elevator doesn't work, my room is too hot or too cold?
2. My Pitt ID will not open the doors!
3. I need access to the copy machine!
4. I need to borrow a projector, a laptop or the conference phone!

HARDWARE & PROCEDURES

Which machines can I use?
Several UNIX machines are available as the department's general use compute servers.

SPARC/Solaris Systems

The Elements Cluster
For Red Hat Enterprise Linux, please connect to elements.cs.pitt.edu (or) linux.cs.pitt.edu.  This will connect you to to one of the multi-processor servers in the elements cluster. The machines in the cluster are:

The Maté Cluster
The department operates a cluster of 16 SunFire X2100 compute servers, each with dual 2.4GHz 64-bit AMD Opteron processors and 4GB RAM. This cluster runs the Condor distributed processing manager on Red Hat Enterprise Linux 4. The control machine for this cluster is s1.mate.cs.pitt.edu. This cluster can be accessed using your departmental computer account and without prior authorization.

PittGrid
The department participates in the University-wide distributed computing project known as PittGrid. See their web site for more information.

PlanetLab
PlanetLab is a distributed network testbed spanning over 450 sites with more than 1,000 nodes around the globe. The main goal of the testbed is to encourage the development and deployment of innovative network services utilizing geographically dispersed points of presence around the world. Thousands of researchers from top academic institutions and industrial labs actively use PlanetLab to develop Internet-scale distributed storage, P2P systems, distributed hash tables, query processing and so on.

The University of Pittsburgh is a proud member of PlanetLab and currently contributes two nodes to the testbed. In order to use the testbed, one needs to sign up for a user account and ask the site PIs (KyoungSoo Park or Alex Labrinidis) to approve and create a slice. More information can be found at the PlanetLab homepage: http://www.planet-lab.org

Computing Labs
There are also 2 computing labs available for your use.  The Link-to-Learn lab in room 5712 and the Moyé Lab in room 5806 have PCs running Windows and can, in addition, be used to connect to the UNIX compute servers mentioned above.

How do I connect to the CS UNIX servers?
You can connect to the servers using "putty", an SSH client program that has been installed on the departmental Windows machines, or by using ssh from another UNIX machine.  For security reasons, the department does not accept telnet connections to our servers. 

• If you are trying to log into the console of a UNIX workstation, press return once or twice to clear the screensaver. Enter your username and password at the prompts; most workstations in the department are running the X Display Manager interface (XDM).
• Note that the University retired the modem pool it hosted at 412-297-7488 on January 31, 2012. If you are dialing in on a modem, you will need to use your own ISP.

The printers listed below are available to be used appropriately (see next question) by all faculty, staff, and graduate students in the department. The printers and their locations are:
 

ps
    5414, 5th floor Mail Room

cps5414 (color printer for faculty, staff and graduate students)
    5414, 5th floor Mail Room

ps2
    6146, 6th floor Mail Room

color-ps (color printer for faculty and staff)
    6146, 6th floor Mail Room

ps6w
    across from room 6415

ps6n
    across from room 6103

ps5712
    5712, Link to Learn Lab

moyepr
    5806, Moyé Lab

Some faculty also provide printers for their students to use.  The use of these printers is restricted.

What is appropriate use of the printers?
The printers should be used only for class work, departmental business, and supervised research. The printers are not for personal business.

How do I send files to the printers?
For general printing of text and PostScript files there is the standard UNIX lpr command and there is the Adobe enscript command.

The lpr command will print both text and PostScript files with limited formatting and control options. You must specify which printer to send your output to. The syntax is:

The enscript command, on the other hand, converts text files to POSTSCRIPT language format for printing. It will perform the conversion according to the command line options specified (see the man page) and spool the file for printing in one operation. Here again, you must use the -P option to specify the printer you want to use. Enscript has many options including page numbers, page headings, two column output, landscape mode printing, and more. See the man page for more information.

If the -P option is not specified, both commands will look to the PRINTER environment variable set for your shell and try to send the output to this printer. The command 'printenv PRINTER' will display the value for this variable. The command 'setenv PRINTER mib' will set the value of this variable to "mib". The setenv command is typically set in the .cshrc file located in each user's home directory.

Note that compressed files must be uncompressed before they can be printed. Photo image files may be printed only from a web browser or photo editing program. Printing a compressed file or a photo image file will jam the print spooler and hold up subsequent processing. If you suspect this has happened, send e-mail to the tech staff. Compressed files can be recognized by a .z, .Z, .gz, .zip, .gzip, .tar, .rar, or .bz2 suffix. Photo image files can be recognized by a .jpg, .gif, .tif, or .targa suffix.

To use the printers under Windows you must have the printers installed on your workstation.  Send an e-mail to tech@cs.pitt.edu to request that a printer be installed on your workstation.

How do I send pdf files to the printers?

pdf files cannot be sent directly to the printer. As with compressed and photo image files, sending a pdf file directly to the printer will cause it to jam or otherwise waste paper and not print correctly. Instead open the file using Adobe Acrobat Reader (or other software capable of opening an Adobe Acrobat file) and print the file from within that. In UNIX, one command for this is: acroread <filename.pdf>.

Where are the departmental photocopiers?
Photocopy machines are available in the Mail Rooms (5414 and 6146).

Please see Angela Ellis in room 6145 to get an authorization code to use the machines.

How can I access the wireless network in Sennott Square?
You may access CSSD's "WIRELESS-PITTNET" in Sennott Square.

For details about configuring your laptop for "WIRELESS-PITTNET" see:
http://technology.pitt.edu/network-web/wireless.html

How can I get information about the video conferencing room in Sennott Square?
The users manual for the Eli Lilly Conference Room in 6106 Sennott Square can be accessed here.

What are the configurations of the public printers?

Queue	Model	Tray 1 Sheets	Tray 2 Sheets	Tray 3 Sheets	Tray 4 Sheets	Tray 5 Sheets	Tray 6 Sheets	Memory	Duplexer Available
ps2	Xerox Phaser 5550DT	100	500	500	500	500	3500	1 GB	Yes
color-ps	Xerox Phaser 6360DT	100	500	500	N/A	N/A	N/A	768 MB	Yes
ps6n	HP LaserJet 4300	100	500	1500	N/A	N/A	N/A	80 MB	Yes
ps6w	HP LaserJet 4300	100	500	500	1500	N/A	N/A	80 MB	Yes
ps	HP LaserJet 4350	100	500	500	1500	N/A	N/A	96 MB	Yes
cps5414	Xerox Phaser 8560DN	100	500	N/A	N/A	N/A	N/A	256 MB	Yes

The printers are loaded with 8 1/2 inch by 11 inch size paper. This size is commonly known as LETTER size. We do not use A4 size paper which is common in Europe and China. When installing printer drivers you may need to change the default paper size from A4 to LETTER.

How do I configure my Windows 7 machine to print?
To add these printers on a Windows 7 machine for use inside the department's network you must first install the LPR software. To install the LPR software go to START then Control Panel, click Programs and Features, click Turn Windows features on or off, expand Print and Document Services, select the LPR Port Monitor check box, and then click OK. This may take a few minutes to load. Once the LPR software is installed you may add as many printers as you like.

Adding printers in Windows 7 is done by going to START, Devices and Printers, Add a printer, Add a local printer (this is not intuitive, but Windows considers printers linked by LPR to be local and NOT networked), select "Create a new port", choose "LPR Port", click NEXT.

A new window will open and request 2 entries. The "Name of the server providing lpd" is always "printsrv.cs.pitt.edu". The "Name of the printer" will be the printer you wish to install, such as ps2, color-ps, ps6n, etc.

Windows now asks you to install a printer driver. Select the manufacturer of the printer from the left box and the printer model from the right box. You can determine this from the table above or by visting the printer's web page. For example, if you visit ps2.cs.pitt.edu you'll quickly see its model number and manufacturer.

If you do not see the model of the printer listed, press the "Windows Update" button and Windows will find more drivers for you. Choose a postscript driver (the name usually ends in PS). Click "NEXT".

Windows now asks you to name the printer. Choose something like "queue-name-here via LPR". For example, for the ps2 queue, choose "PS2 via LPR". You may rename this printer at any time, so the name you choose is not critical. Click NEXT.

Windows next asks if you wish to share this printer. Choose "Do not share this printer". Click NEXT.

Windows now allows you to print a test page and decide if you wish to use this printer as your default. Make your selections and Click FINISH. Note that you may change your default printer at any time, so this choice is not set in stone!

Your printer is now installed. You may wish to enable features, such as duplex printing. Or you can start using it right away. If you wish to customize the printer settings, right click on the printer and select "Printer Properties" and/or "Printer Preferences". Each driver is unique, but inside "Printer Properties" you'll find a "Device Setting" tab that will allow you to enable "Installable options" such as duplex printing. Inside "Printing Preferences" you'll find a "Finishing" tab that will allow you to use "Duplex printing" as your default. You may find that you must first enable duplex printing inside "Printer Properies" before you can see it in "Printing Preferences". Again, each driver is unique so the tab names may vary.

If you have any questions or problems installing a print driver, or do not feel comfortable attempting this, just contact the tech staff via the ticket system. We will happily arrange an appointment to demonstrate to you how printers are installed and will setup the printers for you.

How do I configure my Macintosh to print?
All printing is done using the LPR/LPD protocol to our print server, printsrv.cs.pitt.edu.

Determine the manufacturer and model number of the printer you wish to use and download the correct driver from the manufacturer's web site. When you install it, it may try to take you through a dialog to add a printer definition. You can try that, making sure to specify LPD printing over IP to printsrv.cs.pitt.edu using the name of the printer as the queue name. If it does not prompt you to add a printer definition, or if the definition doesn't work, then follow these steps:

• Click on System Preferences->Print and Fax. If necessary, click on the padlock and enter your password to make changes.
• Click on the + sign to add a printer.
• Click on IP
• Set the Protocol to Line Printer Daemon - LPD
• Set the Address to printsrv.cs.pitt.edu
• Set the Queue to the name of the printer, e.g. ps2
• Set the Name to the name of the printer, too.
• (optional) Set the location to the building and room number, e.g. 6146 SenSq
• Set the Print Using to "Select a driver to use..."
• Choose the correct driver for the make and model printer you wish to use
• Click Add

SOFTWARE & PROCEDURES

Why can't my directory under public/html be seen?
The web server will not default to a directory listing if there's no index.html file or a scripted equivalent (index.htm index.shtml index.cgi index.php index.phtml). There are two solutions: (a) generate a quick index.html file, or (b) you can disable this feature on a per-directory basis by creating a file called .htaccess in the directory in which you wish to enable browsing. In this file, put a single line that says

Under AFS, this command replaces the UNIX "passwd" and "yppasswd" commands since user passwords are controlled and verified by the AFS Authentication Server, Kerberos.

The second password is for the Microsoft Windows environment.  You can change this password press CONTROL-ALT-DELETE while logged into your workstation and select the "Change Password" button.

While many people use the same password for both environments, it is important to remember that they are separate, independent systems.  Changing the password in one environment has no effect upon the other.

How do I check my e-mail?
To read or send e-mail, one of several mail readers that are installed on the department systems can be used.  These include: Pine, Mutt, Thunderbird, Outlook and Windows Live Mail.   You may also use any modern web browser and connect to either https://webmail.cs.pitt.edu or https://my.pitt.edu.   You can login to either of these using your Pitt account username and password.  These websites may be accessed from anywhere on the Internet and no setup is required on your part. For assistance with e-mail setup, including configuring of e-mail clients, see the Computing Services and Systems Development (CSSD) web site http://technology.pitt.edu/help/help-index/email-accounts-help.html

What is my e-mail return address?
Your e-mail address is your username (i.e. your login name) followed by "@cs.pitt.edu".  For example, if you login with the username of "john", your address for this login account would be "john@cs.pitt.edu".

How do I read my e-mail from home?
CSSD provides mail servers for IMAP, SMTP and Exchange. You will need to configure your mail reader on your home PC to make use of one of these servers:

IMAP: imap.pitt.edu
SMTP:  smtp.pitt.edu
Exchange: mail.pitt.edu

What is the URL for my home page?
Setting your web browser to the URL: 'http://www.cs.pitt.edu/~username'; will display the file ${HOME}/public/html/index.html, if it exists. The index file may also be named any one of these: index.htm index.shtml index.cgi index.php index.phtml.

What kinds of programs are there on the CS machines?
All the typical UNIX utilities for job control, file manipulation, networking (ssh, sftp, etc) and C compilation and debugging can be found on each of the department systems, as well as a lot of public domain software.

Some directories worth mentioning are:

/usr/local/bin          - contains host dependant software not part of
                          stanard UNIX and may vary from machine to machine
/usr/local/X11/bin      - contains host dependant X11 software
/usr/local/contrib      - contains user contributed & maintained software

What information is available online?
General information about both the University and the Computer Science Department can be found in their respective home pages (http://www.pitt.edu and http://www.cs.pitt.edu).

How do I logout?
Logging out depends on the UNIX shell (command line parser) and/or the windowing system (if logged in at a UNIX workstation) you are using.

By default, typing Control-D will exit any of the UNIX shells. In this case, Control-D indicates the end of file; here the end of the standard input (stdin) stream. Be careful when using programs that use Control-D to terminate; typing one too many Control-Ds may actually log you out of the system prematurely. Most UNIX shells allow this feature to be disabled by setting a shell variable called "ignoreeof". When set, the user must type exit or logout, depending on the shell, to either leave the current shell or logout of the machine completely.

The following table summarizes the different shells and their various means of termination: 

What do I do if I suspect I am having a hardware or software problem?
If applicable, consult the man page to be sure you are using the command correctly. In many cases, other students may be of help. If the problem persists, you suspect a machine is down, or can not access files you previously had access to, send e-mail to tech@cs.pitt.edu. Describe the problem as thoroughly and succinctly as possible, including as necessary, the name of the command, the path of the command, the machine in question, and other pertinent symptoms/conditions. In some cases it may be necessary to include the conditions required to duplicate the problem.

Mail sent to tech@cs.pitt.edu is entered into the tech queue of the Department's ticket system and is read by the technical support staff.  In most cases, we can respond to your request rather quickly, however some requests will take longer.  Please be patient.

How do I set up my UNIX account to use LaTeX?
Edit your .cshrc file or equivalent and add the following statement at some point after the code used to set your shell "PATH" variable:

source /usr/local/etc/latex.env

Users can make additional modifications to the variables set in this file if necessary.

NOTES:

Note that if you are using the department standard cshrc script you need not do anything. This shell script executes latex.env for you. Customizations to your latex environment may be made in your .cshrc.custom file.

How do I set up my UNIX account to run other software in the Department?
Every time you log on, the file .login. Every time you open a window or create a shell, the file .cshrc is read and executed. The following are the standard .login and .cshrc distributed by the Department.

Edit your .login file to look like this:

source /usr/local/etc/login

source /usr/local/etc/cshrc

How do I set up my Windows machine at home to be able to access AFS files?
First, go to the OpenAFS website at:  http://www.openafs.org/ and download the latest OpenAFS client for Windows.

Next, click on the executable you downloaded to begin the installation process. Use the default settings on most menus.

At the "Client Cell Name Configuration" screen, enter "cs.pitt.edu" for the AFS cell name.

After installation reboot your computer. Login and authenticate to AFS.

It is now time to map an AFS drive to a drive letter. You do this via the "MAP NETWORK DRIVE" menu by right clicking on "MY COMPUTER" (or "COMPUTER" depending upon your version of Windows). The general syntax is \\afs\cs.pitt.edu where "afs" is the "server" and the "cs.pitt.edu" path is the "share".

To map to a specific afs path, just enter the path after the share "cs.pitt.edu". For example, to map to the files of username "maestro" the syntax would be \\afs\cs.pitt.edu\usr0\maestro

Another important mapping you may want to create is the "all" mapping. This maps the AFS root cell to a drive-letter of your choosing. This will allow you to read and share files in world-wide AFS cells including the cs.pitt.edu cell.

This is accomplished using the syntax \\afs\all

The standard drive mappings that we use on the departmental Windows machines are:

• M: - the currently logged on user's home directory
• N: -  the AFS root cell

How do I verify if the message I got about a virus is true or not?
You can check the Hoax Buster's Web site if you suspect a hoax (not a true virus) or see  the Urban Legend Reference Web site for urban legends.  Also the Symantec Antivirus home page is an excellent place to check on the latest virus threats.

Why do I sometimes get 2 requests for passwords when logging into Linux?
That's the behavior of the PAM module under Linux. If your AFS password is incorrect, it then prompts you for your local password.

PAM is the Pluggable Authentication Module. It is supported on most of our architectures, such as Solaris and Linux. You can look at the The Linux PAM web page.

How can I look and edit MS Office (Word, Excel, etc) files in the UNIX machines?
StarOffice is installed in /usr/local/contrib/bin; this should be in your $PATH. To invoke StarOffice type 'soffice' at the command prompt.

How can I add to my $PATH variable?
At the command prompt type the following

setenv PATH ${PATH}:<path-to-be-added>

How can I install programs (for everyone to use and not using my own disk quota) in the UNIX machines?

1. Send a request to tech@cs.pitt.edu and request to be added to the contributor's list.  Be sure to specify what you want to install in this e-mail!
2. Download the software into the contrib directory, untar, etc.
3. Install the software for as many platforms as possible.  Here is a list of the platforms we currently support:

        - any of the Elements machines for Red Hat Enterprise Linux (see the chart at the top of this page for the different RHEL variants)
        - blitz.cs.pitt.edu for Solaris 9
        - hydra.cs.pitt.edu for Solaris 10
       
4. The install procedure is as follows:

1. There is a directory under /usr/local/contrib that you add the software to.  Unzip the software and add the sources to /usr/local/contrib/XXX/src and add the binaries to /usr/local/contrib/bin (NOTE:  No XXX in the bin directory, it is pure /usr/local/contrib/bin).
2. Write a documentation or README file that will reside in the /usr/local/contrib/XXX directory.  This should include the paths and the variables that the software requires.  If the usage is complicated, a script should be created to facilitate using the program.
3. Install the man pages in /usr/local/contrib/man.

Thanks again for volunteering!  We truly appreciate it!  Also, let tech know if you have any problems.

How do I create a symbolic link in UNIX?

ln -s <path-to-original-location> <path-to-link-destination>

How to have email forwarded to another address?

Suppose you want your email forwarded to other_address@wherever.com. You must be a user of Pitt's IMAP service. Users of Enterprise Exchange cannot forward their email off-site.

Log on to https://my.pitt.edu and click on Edit forwarding addresses on the right-hand side of the screen.

For the 5502, 5505 and 6110 labs, there is a method for turning off network access to the internet in general, or to limit traffic to just within the department.

Visit http://labaccess.cs.pitt.edu/ . If you are unable to log in, you'll need to request access from tech

• 7-Zip
• Adobe Flash Player
• Adobe Reader
• Adobe Shockwave Player
• Alice 2.2
• Blender
• GIMP
• GLUT 3.7.6
• GSview and Ghostscript
• Java3D
• MARS
• Microsoft Internet Explorer 8
• Microsoft Office 2010
• Microsoft Silverlight
• Microsoft Visual Studio 2010
• Mozilla Firefox 3.6.x
• NetBeans
• Notepad++
• OpenAFS Client
• Oracle JDK and JRE
• Python 2.7
• Putty
• Scratch
• Symantec Endpoint Protection
• VLC Media Player
• WinSCP

• CUDA Drivers and SDK
• Maya 2009
• PhotoShop CS4 (installed only on two machines)
• UT3

• Camtasia (installed only on one machine)
• Dreamweaver CS4
• Google Earth

• Setting up IPSec on Windows Systems: http://technology.pitt.edu/Documents/network/secure-remote-access/IPSec_Windows.pdf
• Setting up IPSec on Macintosh Systems: http://technology.pitt.edu/Documents/network/secure-remote-access/IPSec_Mac.pdf
• Setting up IPSec on Linux Systems: http://technology.pitt.edu/Documents/network/secure-remote-access/IPSec_Linux.pdf

DISKS & FILES

What do I do if I need more disk space?
User accounts are initially created with a default disk quota. Occasionally more disk space may be needed for data intensive applications. If you need more disk space, you should send e-mail to tech@cs.pitt.edu requesting more space and why you need it.

The AFS command "fs lq" will tell you your disk quota (in 1-Kbyte blocks), how many of those blocks are currently used, the percentage used, and the percentage of space used on the disk partition that you share with other users. Note that this command will tell you this information about the AFS volume that your current working directory resides in. If your username does not appear in the volume name listed with this command just "cd" to your home directory.

The UNIX command "du" will give you a block count and an idea of how much space is being used by a individual directories and files. See the man page for this command for the particular workstation you are on.

How are my files set up?
The Computer Science Department uses the Andrew File System (AFS) to manage user accounts. This distributed file system allows user accounts to be accessed from any department machine as well as any other machine located throughout the world provided that machine is running AFS. A user does not need an account on remote sites to access AFS volumes and the files that they contain provided the appropriate AFS access rights are granted for these directories. If a user does have an account at another AFS site such as the University's CSSD department, these files may be accessed from this department's machines without having to log into University machines (see How do I access other AFS cells? below).

When you log into a UNIX machine, your current working directory is set to your home directory. Your home directory and all files and subdirectories are stored in what is called an AFS volume (or simply volume) which can be displayed by the AFS command "fs lq".

A user's home directory is initially set up with two subdirectories called "public", and "private", and a symbolic link to a backup directory called "Backup". The AFS access rights for each of these files is appropriately set and should not be changed. The public directory is world readable and is intended for sharing files with others and holding the user's World Wide Web home pages. The private directory is intended for personal files that a user wishes to protect from world-wide and local users.

A user's home directory can usually be referenced in UNIX shell commands by the syntax "${HOME}" or "~", the tilde character; the former syntax is the preferred method when referencing the home directory from shell scripts.

Access to particular files within a user's home directory is controlled by AFS access rights. The usual UNIX mode settings controlled via the UNIX command "chmod" are meaningless when the file or directory is located within an AFS volume.

How do I control access to my AFS files?
Access to individual directories in your home directory by you and other users is managed under AFS by way of Access Control Lists (ACLs). ACLs are maintained for each directory in your volume and are under your control. Directories in your volume are still created with the UNIX "mkdir" command, but access is controlled via AFS. The ACL for a newly created directory inherits the ACL of the parent directory.

An ACL has two parts: a user or group name and the access control rights. The user/group name and the "rights" are separated by a space. The seven access rights are indicated by letters or, alternatively, one of four "shorthand" words used to represent more frequently used subsets of these rights:

Access Control Rights		Shorthand Notation
r: read	d: delete	read = rl
l: lookup	w: write	write = rlidwk
i: insert	k: lock	all = rlidwka
a: administer		none = removes entry

The AFS command used to set and modify ACLs is the "fs" command. Limited help is available on the man page for this command. A synopsis of these commands may be displayed by typing "fs -help", "fs listacl -help", and "fs setacl -help".

EXAMPLES:

1. List ACL for current working directory:
                   fs listacl
2. List ACL for the directory dir:
                   fs listacl dir
3. Give user john all rights to dir:
                   fs setacl dir john all
4. Revoke all rights to group system:anyuser (The following command should be used when creating a new mail directory.):
                   fs setacl Mail system:anyuser none
5. Provide user john with write access and user jane with read access to all files in the current working directory:
                   fs setacl . john write jane read (or fs setacl . john rlidwk jane rl)

 

find . -type d -exec fs sa -dir \{\} -acl foo baa \;

If you discover the error the same day (i.e. before the next nightly backup is done), you can quickly recover the file yourself. Each weeknight, a copy of all files within your AFS volume is backed up to a separate volume pointed to by the symbolic link called "Backup" in your home directory. You may use the UNIX command "cd" to get to this volume and its subdirectories which is a mirror of your home directory for the previous day.

Once you locate the file in question, use the UNIX "cp" command to copy this file to the appropriate spot in your home directory. See the "cp" man page for the system that you are logged onto; there are slight variations between UNIX platforms.

It is faster to recover files yourself from the ${HOME}/Backup directory whenever possible since it does not involve the staff loading tapes when time permits.

When I do an "ls -l" on the '/afs' directory, my terminal hangs. Why?
AFS provides a file system which allows files to be distributed anywhere in the world. The subdirectories of /afs, called cells are actually pointers of sorts to other locations around the world. The /afs directories provide access to files contained within these cells according to the same AFS access rights discussed above.

The information that you request with the -l or -F option when invoking the ls command is actually kept at these remote locations. These specific options will cause AFS processes to contact remote AFS processes to gather statistics about the relevant directory entries. Depending on the number of locations contacted, their distance from the local cell (in this case, cs.pitt.edu) and the random occurrence of network failures, it can take a very long time to complete the commands: "ls -l /afs" or "ls -F /afs".

If you have inadvertantly, or otherwise, executed these commmands on remote /afs entries, you can check which ls command you are using by the commmand "which ls" at a later time - you may have it aliased to one of these.

To try and abort this command is at times difficult. You can try typing ^c (control-c) to interrupt this command or, if this does not seem to work, try typing ^z to suspend this command. If this works, your prompt will come back and you will be able to type the jobs command to see the suspended job. Then type "bg" to run this command in the background, followed by "kill %" to interrupt the most recent job put in the background. This may take a moment or longer; kill will send a terminate signal to the ls process which may be too busy at the moment to catch this signal and respond right away.

If you really want to use these forms of the ls command on remote AFS sites, it is usually less frustrating to limit your inquiries to one or a few cells.

How do I access other AFS cells?
You do not need to have a user account at another AFS site (cell) inorder to access data stored at the sites listed in /afs. Simply follow the directory hierarchy using the UNIX cd command for the chosen site. It may take a while for the data to be transferred from the remote site for this command to complete. The usual UNIX commands for reading and copying files apply, but you will only be able to access files that are AFS publicly readable as granted by the owner of the file(s).

If you do have an account at another cell, as many of us do from previous undergraduate AFS sites, or currently at this University's CIS department, you do not need to directly log into the University's machines to gain full access to your files in this account. For example, if you have an account at Pitt CIS (another AFS site) you can gain full access rights to your remote files by authenticating with the remote cell site; in this case "pitt.edu". To do this, the AFS "klog" command is used. You will need to know the name of the remote cell, your username for the remote account, and you will be prompted for your remote password:

klog -principal username -cell pitt.edu

NOTES. The AFS command "tokens", will tell you what cells you are currently authenticated for. The AFS command "unlog -cell pitt.edu" will discard the token for access to the specified cell; careful... not specifying a cell will discard all tokens including access rights to your home directories. If this happens just klog again with no parameters; your current login cell is used by default.

I frequently have problems accessing files after I have been logged in for a long time. Why?
When logging into an AFS site such as the Computer Science Department, you are authenticated (i.e. verified) as a user in this department's AFS cell. The authentication process associates a token (also referred to as a ticket) with your login process. The token you receive at each login is good for a period of 25 hours. If you are logged in for more than this time, your token automatically expires and you will not be able to access files in your home directories that are not publicly readable/writeable. To get a new token, issue the AFS command "klog"; you will be prompted for your password and reauthenticated.

How do I clean up my account to get more space (core files specifically)?
Core files are dumps of memory that are kept in a file for debugging purposes when a program crashes. Typically you do not want these on your directories, since they are rather large files. You can periodically run a command that finds and removes the core files:

find ~ -name core -exec /bin/rm {} \;

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