#!/bin/sh
# David Jones and Will Furnass (University of Sheffield)

# `qrsh` is often the most convenient utility for starting interactive shell
# sessions on Sun/Son of Grid Engine (SGE) clusters but it has some limitations (as
# configured on the ShARC/Iceberg clusters):
# 
# - none of the standard SGE environment vars (e.g. JOB_ID, PE_HOSTFILE,
#   NSLOTS) that are defined in qsub/qsh batch/interactive sessions are set
#   (annoying but not the end of the world);
# - variables can't be set in prolog scripts (e.g. the CUDA_VISIBLE_DEVICES env
#   var needed for exclusively locking GPUs to jobs);
# - X display forwarding doesn't work.
#
# This script addresses these three issues.  It starts a qrsh shell session in
# which:
#
#  - all environment variables set by the scheduler (e.g. JOB_ID) are set
#  - X display forwarding is enabled if necessary

exec qrsh $( [ -z ${DISPLAY+x} ] || echo '-v DISPLAY' ) -pty y "$@" $SHELL