This requires the installation of ldg-4.5

 - source the ldg-4.5 setup file, eg "source ~/ldg-4.5/setup.sh"
 - enter the command "grid-proxy-init"
 - type in your password when prompted
 - enter "ssh ldas-pcdev1.ligo.caltech.edu" (you may replace "pcdev1" with "pcdev2" or "grid" to log-in to a different head node)