a script that writes to a text file that you can use in OBS for an on-screen meeting timer

meeting_countdown.sh

#!/bin/bash

if [[ $# -ne 1 ]]; then
  echo "Usage: ./meeting_countdown.sh NUM_MINS"
  exit 1
fi

MINS=$1
OUTFILE=~/src/obs/timer_out.txt
MESSAGE="time remaining in this meeting: "

for i in `seq $(($MINS*60)) 1`
do
  sleep 1
  MIN_REMAINING=$((i / 60))
  SEC_REMAINING=$((i - ( $MIN_REMAINING * 60 ) ))
  printf "$MESSAGE %d:%0.2d" $MIN_REMAINING $SEC_REMAINING > $OUTFILE
done

while test 1; do
  sleep 1; echo "$MESSAGE None." > $OUTFILE
  sleep 1; echo "$MESSAGE nOne." > $OUTFILE
  sleep 1; echo "$MESSAGE noNe." > $OUTFILE
  sleep 1; echo "$MESSAGE nonE." > $OUTFILE
  sleep 1; echo "$MESSAGE none_" > $OUTFILE
done

Hey look: months later I actually came back to use this on another computer. Yay me!