The Open Science Grid (OSG) client includes several things which will enable you to submit jobs to OSG compute elements.  These include:

• Globus Toolkit, the defacto core pieces of all grids.  Include web services, GRAM, and GridFtp
  
• Condor-G, which helps manage and coordinate grid jobs
• srmcp, a client for the SRM (Storage Resource Management) protocol
• All the common CA certificates for the Open Science Grid

Throughout the tutorial, we will refer to the root directory of the OSG install as $VDT_LOCATION.  I would recommend that a system-wide install be placed in /opt/osg/client-xxx, where xxx is the version number (currently 0.4.1).  If you are already running condor on the node you install the OSG client on, do NOT install it as root.  If you are installing it just for a single user, it is fine to install it in that user's home directory - perhaps ~/osg-client. 

As with the server side version of the OSG, the package manager used is called "pacman".  Here are commands required to install it (feel free to chose your own installation directory):

mkdir -p ~/pacman
cd ~/pacman
wget http://physics.bu.edu/pacman/sample_cache/tarballs/pacman-latest.tar.gz
tar zxf pacman-latest.tar.gz
cd pacman-3.18.5 #Or whatever version may apply
source setup.sh

Pacman makes the installation of the OSG client and its sub-packages simple:

mkdir -p $VDT_LOCATION
cd $VDT_LOCATION
# export VDT_PRETEND_32=1 ##only needed to get a 32 bit install on a 64 bit machine.##
pacman -get OSG:client

If pacman has trouble detecting your operating system, it might give you an error and ask you to try again passing the  "-pretend-platform=<OS NAME>" flag.  If so, delete the contents of the $VDT_LOCATION directory and try again with the appropriate argument.  For example, on my Fedora Core 5 desktop, I need to use the following command:

pacman -pretend-platform Fedora-4 -get OSG:client

The installation may take quite awhile to complete.  In order to set up the environment, issue the following command:

source $VDT_LOCATION/setup.sh

where $VDT_LOCATION is substituted with the install directory you used above.

Of course, in order to actually do anything useful, you need to have a user certificate, install the user certificate in your home directory, and join the GPN virtual organization.  These activities are documented on the following pages:

• Applying for a UNL user certificate.
• Installing the user certificate in your home directory
• Import the user certificate into your browser.
  
• Join the GPN VO
  

Once you have done all of the above steps, you should at least be able to authenticate and run test jobs at remote resources (note: membership in the VO might take several hours to propogate to remote sites).  To test your authentication at a remote site:

grid-proxy-init
globusrun -a -r gpn-husker.unl.edu

To submit a test job:

globus-job-run gpn-husker.unl.edu /bin/hostname

Once you have gotten this far, you have a working OSG client installation!  You should progress by playing around with our example grid application.