Shell Programming and Scripting

#!/bin/bash --posix
# timer
# *********************************************************
# Generate a 1 second delay and beep.
# Issued as Public Domain, CC0. You may do with it as you please.
# *********************************************************
if [ ! -e "/tmp/sinewave.wav" ]
then
	> /tmp/sinewave.wav
	printf "\x52\x49\x46\x46\x64\x1F\x00\x00\x57\x41\x56\x45\x66\x6D\x74\x20\x10\x00\x00\x00\x01\x00\x01\x00\x40\x1F\x00\x00\x40\x1F\x00\x00\x01\x00\x08\x00\x64\x61\x74\x61\x40\x1F\x00\x00" >> /tmp/sinewave.wav
	cp /tmp/sinewave.wav /tmp/timer.wav
	for n in {0..999}
	do
		printf "\x80\x26\x00\x26\x7F\xD9\xFF\xD9" >> /tmp/sinewave.wav
		printf "\x7F\x7F\x7F\x7F\x7F\x7F\x7F\x7F" >> /tmp/timer.wav
	done
fi
# *********************************************************
# The line below uses various Linux flavours, "aplay"...
# aplay /tmp/sinewave.wav
# *********************************************************
# Use the OSX default basic command line audio player, "/usr/bin/afplay".
afplay /tmp/sinewave.wav
# aplay /tmp/sinewave.wav
# A demo delay of around 6 seconds, about 1.5 seconds per loop.
for n in {1..4}
do
	# aplay /tmp/timer.wav
	afplay /tmp/timer.wav
done
afplay /tmp/sinewave.wav
# aplay /tmp/sinewave.wav
# *********************************************************
exit 0
# Enjoy finding simple solutions to often very difficult problems...

Last login: Thu Mar 13 08:19:23 on ttys000
AMIGA:barrywalker~> chmod 755 timer
AMIGA:barrywalker~> ./timer
AMIGA:barrywalker~> ./timer &
[1] 247
AMIGA:barrywalker~> _

#!/bin/bash

while :
do
    echo pausing...
    read -t 2
done

read -t 3 -s -N 1000000 nop

xrealloc: ../../bash/builtins/../../bash/builtins/read.def:525: cannot allocate 134217840 bytes (536911872 bytes allocated)

#!/bin/bash

while :
do
    echo pausing...
    read -t3 A </dev/zero
done