Question

estion 3 t out of 4 po 1) Write a bash script that checks for options passed to it. Use getopts and while loop as discussed in the classroom. Your script should: (i) Generate error messages (ii) Check for invalid options (ii) Check for options x and y, where option 'y' must take an argument (iv) Print to the screen information informing which (if any) option was triggered 2) Explain your code (either in the comments to the code or underneath of it). Make sure to answer 1) and 2) above.

Answer 1

#!/bin/bash -l
#PBS -l nodes=4:ppn=8,walltime=24:00:00

cat $PBS_NODEFILE | uniq | tr '\\012' ' ' > tmp-$PBS_JOBID
read -a NODE < tmp-$PBS_JOBID
rm tmp-$PBS_JOBID

inode=-1
ijob=0

usage() { echo "Usage: $0 [-s <45|90>] [-p <string>]" 1>&2; exit 1; }

while getopts ":s:p:" o; do
case "${o}" in
s)
s=${OPTARG}
((s == 45 || s == 90)) || usage
;;
p)
p=${OPTARG}
;;
*)
usage
;;
esac
done
shift $((OPTIND-1))

if [ -z "${s}" ] || [ -z "${p}" ]; then
usage
fi

echo "s = ${s}"
echo "p = ${p}"

for ((K=1;K<=8;K++))
do
[ $((ijob++ % 2)) -eq 0 ] && ((inode++))
ssh ${NODE[inode]} _somepath_/RUN$K/sub.script &
done
wait
exit 0