Shell Programming and Scripting

# Call this script with parameters for wait_time, increment, and cycle_count
#
# example sh test.sh 300 1 10
# this will sleep for 300 seconds, increment the start time by 1 second, and run
# for 10 cycles

# Saving variables passed in from command line for later use
wait_time=$1
echo "Wait time in seconds: "$wait_time
increment=$2
echo "Increment in seconds: "$increment
cycle_count=$3
echo "Itteration cycles: "$cycle_count

# Turning network clock off
systemsetup -setusingnetworktime off

# getting on with it
read -p  "Hit any key when ready to begin"
init_time=$(systemsetup -gettime)
echo "Reference time will be set as: "$init_time

# converting current system time to seconds
d=$init_time
IFS=":"
set -- $d
hr=$2
min=$3
sec=$4

# strip leading white space from hr
hr=$(echo $hr | tr -d " ")

# echo "IFS time in seconds: $(((hr*3600)+(min*60)+sec))"
ref_time=$(((hr*3600)+(min*60)+sec))
# echo "\$ref_time set to: "$ref_time

#inserting while loop
COUNTER=0
while [  $COUNTER -lt $cycle_count ]; do
echo Cycle count: $COUNTER
echo "sleeping for $wait_time seconds"

# Don't want to sleep while testing
# sleep $wait_time

# Adding $increment to $ref_time
new_time=$((ref_time+increment))
# echo "old ref_time was: "$ref_time
ref_time=$new_time
# echo "new ref_time is: "$new_time

# Converting new_time to HH:MM:SS for set_time
secs=$new_time
# echo "\$secs set to: "$new_time

h=$(( secs / 3600 ))
m=$(( ( secs / 60 ) % 60 ))
s=$(( secs % 60 ))

echo "system time will be sets as: systemsetup -settime $h":"$m":"$s"
set_time=$h:$m:$s
echo $set_time
# systemsetup -settime $h":"$m":"$s"

let COUNTER=COUNTER+1
done

# Turning network clock on
systemsetup -setusingnetworktime on

IFS=":"

IFS=":"
set -- $d
hr=$2
min=$3
sec=$4

# Adding this as a wild hair, what if IFS above is causing problems?
IFS=";"

OLD_IFS=$IFS
IFS=:
# your commands here
IFS=$OLD_IFS

IFS=$' \t\n'