Computer Science Network Information
The Computer Science Network (csn) is composed of machines
running Solaris, Linux, and Windows operating systems.This document will provide basic information
about the CSN UNIX machines, such as machine names, resources available,
various methods to gain access to those resources and some basic commands.Please feel free to contact us at
csnhelp@cs.ou.edu or call 405-325-5427 if you have any problems or questions.
Accessing the CSN
The first thing needed to access the CSN is a CSN computer
account.This is only needed if you will
be accessing one of the UNIX machines on the CS network.If you will be logging in to a Windows
computer on our network then your account is created and maintained by
ECS.Questions and help with your ECS
account can be obtained by calling 325-4409 or emailing needhelp@ou.edu.
In most cases your CSN account will be auto-generated for each
class that will require assignments be completed using the UNIX
environment.Please check with the TA
for your class to see if it has been auto-generated.If that is not the case then an individual
account can be applied for the CS website at www.cs.ou.edu/students.For auto-generated accounts the username and
password will be communicated to you by your instructor or the TA.Individual account information must be picked
up from the receptionist at the Computer Science offices.
IMPORTANT ACCOUNT INFORMATION
Accounts expire within two weeks after the end of each semester.
Home directories will be purged after the accounts have expired.
50 page per month print quota.Reset at the first of each month.
Armed with your CSN account you are ready to access one of the
UNIX systems.Your instructor or TA may
want you to use certain machines, if so those hostnames will be given to you in
the assignments.Please consult the
following table for to determine which host you need to log in to:
HOST NAME | OS TYPE | ACCESS METHODS |
gpel1 | Linux | SSH, SFTP, EL158 |
gpel2 | Linux | SSH, SFTP, EL158 |
gpel3 | Linux | SSH, SFTP, EL158 |
gpel4 | Linux | SSH, SFTP, EL158 |
gpel5 | Linux | SSH, SFTP, XDMCP, EL158 |
gpel6 | Linux | SSH, SFTP, XDMCP, EL158 |
gpel7 | Linux | SSH, SFTP, XDMCP, EL158 |
apollo2 | Linux | SSH, SFTP, EL158 |
apollo3 | Linux | SSH, SFTP, EL158 |
codd | Linux | SSH, SFTP, EL158 |
hamming | Linux | SSH, SFTP, EL158 |
suman | Linux | SSH, SFTP, EL158 |
All of the machines are in the cs.ou.edu domain, and should be
accessible by their hostname if you are located within the ou.edu domain.If you are outside of the ou.edu domain you
must reference the fully qualified internet domain name,
EXAMPLE:
Sftp is the only allowed ftp
program allowed to move files to machines in the CSN. You can connect to
machines from the CSN with ftp. Both ssh and sftp requirements are
enforced to keep usernames and passwords encrypted and safe from network
sniffers.
Machines with XDMCP allow you to use windows software such as
XWin32 or Exceed to establish an X windows sessions and run X applications
remotely.
Machines with EL158 indicated are located in the CS lab located
in the Engineering Laboratory building (a.k.a. EL) in room 158.Room 158 is located at the east end of the
building.You can sit down and log in
directly from the console on these machines.When logging in to these machines it is recommended that you select CDE
for your window manager.It is a little
more user friendly and supported.Gnome
is also available on these machines but may require a little modification to
your startup files before it will work on the Solaris machines.Roam3 is a Linux machine and only has gnome
and KDE available.
UNIX Environments (shells)
The popular UNIX shells (bash, tcsh, sh, csh) are available on
our network.All auto-generated accounts
will be set up to use the bash environment.Some common interactions with your shell are:adding or changing environment variables,
using tab completion, command history, each described below:
Environment Variable Maintenance
Add or changing variable to your environment:
bash:export
<VARNAME> = <VALUE>
tcsh:setenv
<VARNAME> <VALUE>
EXAMPLE:To
add the value /home/ralf1345/bin to my system PATH
bash: export PATH =/home/ralf1345/bin:$PATH
tcsh:setenv PATH =/home/ralf1345/bin:$PATH
Tab Completion
Both shells allow for tab completion.Tab completion is pressing the tab key while
typing a command and the shell will automatically complete what it can match up
to a point of difference.
EXAMPLE:I
have three files named:myinput.data,
run1output.data, run2output.data.I want
to print the files at some point and type the following:
lp my<TAB>
When I press the tab key the shell fills in with the rest of the filename for myinput.data.Then I can simply press <Enter> and the command executes.Now I want to print the run2output.data file and I type:
lp ru<TAB>
Now the shell fills in up to the "n", since it doesn't
know whether to choose 1 or 2.At this
point pressing TAB twice rapidly will list the near matches.At that point I enter a 2 and then <TAB>
again and the rest is completed.
Command History
Using the up and down arrow keys you can scroll back and forth
through previously entered commands.They are editable.This can save
a lot of keystrokes and help you remember previous commands from previous log
in sessions.
Important Environment Variables
PATH - The PATH variable is a list of
directories that the shell / OS will search through for the given command.The default PATH is adequate in most
cases.Certain classes may require that
you update your path to point to special programs.
LD_LIBRARY_PATH - When you are compiling programs that you
have written or modified, and you need to compile them, you may encounter
errors stating that certain libraries could not be found.The default LD_LIBRARY_PATH is adequate in
most cases, but may need to point to additional directories containing the
libraries you need.
Help
Help on UNIX commands and programs are available from many
sources.The most common is the man page
system.To access help for a command
from the man page system simply enter:man <command>
This will display the syntax and useful information for the
command in question.A second form of
help is through the info system.This is
presented in more of a manual format.Not all UNIX commands have info formatted files, but info will return a
manpage for the command/program in question.The Computer Science website www.cs.ou.edu/students has many helpful
links.You can download the latest
version of the ssh client for windows from here.Also using google (www.google.com) you can
find a wealth of information on practically any UNIX topic you may be
interested in.
Common Commands
ssh - Use to establish a secure encrypted connection to a remote
computer:
ssh <username>@<hostname>
sftp - Secure replacement for ftp.
sftp
<username@<hostname>
cd - Change Directory.
cd ~- Will change your present working to your
home directory.
cd
<pathname> - to change the present working directory to <pathname>.
pwd - Print the present working directory.This is a good idea before removing or
copying files.
pwd- Will simply print the present working
directory to stdout.
cp - Copy files.
cp <filename1>
mv - Move a file from one location to another.Useful for renaming files.
mv
<filename1> <filename2>
lp or lpr - Use to print a file.
UNIX File Editor programs
The CSN has the following file editors installed:
vi, pico, gvim, emacs
Each editor accomplishes the same tasks.It is purely a personal preference on your
editor of choice.There are many
websites dedicated to the different editors.Man pages or info manuals are available.
Compilers
The CSN has the following compilers installed and available:
gcc, g++, and g77
The TA for each class will instruct you on the use or
requirements for your assignments.Man
pages, Info, and google are excellent resources for resolving questions related
to compiling problems.Remember the
LD_LIBRARY_PATH variable.It can solve
many problems.
Tech Support
Please email questions to csnhelp@cs.ou.edu, and you should get
a response within 24 hours or stop by our offices in the Engineering Lab room
113 or call 325-5427.
Backing Up Your Data
As mentioned earlier your auto-generated classroom account will
expire between semester and your home directory will be purged.If you would like to save a copy of your
files then you may want to use the following suggestions:
create a backup file containing all of your home directory with the tar command:
tar cvf
/tmp/csfall2002.<username>.tar/home/<username>
Now compress the file: gzip /tmp/csfall2002.<username>.tar
Then sftp it to an offsite location: sftp <username>@lincoln.ecs.ou.edu
And finally delete your tar file:rm /tmp/csfall2002.<username>.tar.gz