#!/bin/sh -u
# demo script to try two different SIGINT trap lines
#
#   $0 (no arguments)
#
# Demonstrate how the "trap" command affects scripts and the commands
# that are run by scripts.
#
# NOTE: This script fragment is incomplete - it does not follow all
# the script guidelines set out in "script_style.txt".  It also
# contains many "Instructor-Style" comments that you must not use in
# your own scripts.  See script_style.txt for details.
#
# -IAN! idallen@idallen.ca

PATH=/bin:/usr/bin ; export PATH
LC_COLLATE=C ; export LC_COLLATE
LANG=C ; export LANG
umask 022

# Un-comment one line to compare how ignoring interrupts works:
#  - Disabling interrupts entirely means nothing interrupts the script
#    or any of the commands it runs.
#  - Giving a trap command string means that commands that the script
#    executes can be interrupted; but, the script itself will not exit.

# trap '' 2                         # completely ignore SIGINT
# trap 'echo Interrupt!' 2          # script traps SIGINT; commands do not

let x=5
while [ $x -gt 0 ] ; do
    echo "x is $x"
    let x=x-1
    sleep 3
done