How to parse command-line arguments in a bash script
while [ $# -gt 0 ]; do
case "$1" in
-p|--p_out=*)
p_out="${1#*=}"
;;
-a|--arg_1=*)
arg_1="${1#*=}"
;;
*)
printf "***************************\n"
printf "* Error: Invalid argument.*\n"
printf "***************************\n"
exit 1
esac
shift
done