60 second Timer with Shell Script

Shell Programming and Scripting
1

Please how can i display a 60 second active countdown timer in an echo message.

2

e.g.

#!/bin/ksh
for (( i=60; i>0; i--)); do
  sleep 1 &
  printf "  $i \r"
  wait
done

This work in ksh as well. For posix you probably have to use a while loop.

3

Hi

this is not the best solution, but you can improve it.

input=60
tic=`date +%S`
elap_time=0

while [ "$elap_time" -le "$input" ]; do

toc=`date +%S`
elap_time=`expr $toc - $tic`
done

echo "time elapsed"

EDIT: Sorry I don't answ to your question, becouse you want display it.

Bye

4

Works (almost) fine in bash, too. But I don't understand the use of the sleep command as a background process. Furthermore, the "done" messages caused by returning sleeps disturb the display :frowning:

Nevertheless, much simplier would be just the good ole

sleep 60; echo "\a"

BR,

pen

5 
countdown()
{
  countdown=${1:-60}   ## 60-second default
  w=${#countdown}
  while [ $countdown -gt 0 ]
  do
    sleep 1 &
    printf "  %${w}d\r" "$countdown"
    countdown=$(( $countdown - 1 ))
    wait
  done
  printf "\a"
} 2>/dev/null
6

Hi Pen, the sleep in the background ensures that you use as little time as possible processing the other commands in the loop. Otherwise total sleep is sometimes a bit more than 60 seconds.
You'll get done messages if you execute it from the command line, not if you execute it from a script. Alternatively you can enclose it in parentheses like so:

(for (( i=60; i>0; i--)); do
  sleep 1 &
  printf "  $i \r"
  wait
done)

Then you won't get the pesky job status.
Or you can put it in a function like CFA suggests..
(BTW I just changed the \b\b for \r because now I realise the backspaces weren't working properly).

Indeed, but it is my understanding that the OP requested a countdown timer.

7 
i=60;while [ $i -gt 0 ];do if [ $i -gt 9 ];then printf "\b\b$i";else  printf "\b\b $i";fi;sleep 1;i=`expr $i - 1`;done
8

(Code reformatted for legibility.)

That loop will take noticably longer than one second, due partly to the unnecessary external command.