# script to create timer in terminal
# Jason Atwood
# 2013/6/22
#!/bin/sh

# start up
echo "starting timer script ..."
sleep 1 # seconds

# get input from user
echo "Timer for how many minutes?"
read DURATION
DURATION=$(( $DURATION*60 )) # convert minutes to seconds

# get start time
START=$(date +%s)

# infinite loop
while [ -1 ]; do
clear # clear window

# do math
NOW=$(date +%s) # get time now in seconds
DIF=$(( $NOW-$START ))  # compute diff in seconds
ELAPSE=$(( $DURATION-$DIF ))    # compute elapsed time in seconds
MINS=$(( $ELAPSE/60 ))  # convert to minutes... (dumps remainder from division)
SECS=$(( $ELAPSE - ($MINS*60) )) # ... and seconds

# conditional
if [ $MINS -eq 0 ] && [ $SECS -eq 0 ] # if mins = 0 and secs = 0 (i.e. if time expired)
then # blink screen
for i in `seq 1 180`; # for i = 1:180 (i.e. 180 seconds)
do
clear # flash on
setterm -term linux -back red -fore white # use setterm to change background color
echo "00:00 " # extra tabs for visibiltiy

sleep 0.5

clear # flash off
setterm -term linux -default # clear setterm changes from above
echo "00:00" # (i.e. go back to white text on black background)
sleep 0.5
done # end for loop
break   # end script

else # else, time is not expired
echo "$MINS:$SECS"  # display time
sleep 1 # sleep 1 second
fi  # end if
done    # end while loop