Sleep until a specific time/date

Question

I want my bash script to sleep until a specific time. So, I want a command like \"sleep\" which takes no interval but an end time and sleeps until then.

The \"at\"-d

Answer 1

 function sleepuntil() {
  local target_time="$1"
  today=$(date +"%m/%d/%Y")
  current_epoch=$(date +%s)
  target_epoch=$(date -d "$today $target_time" +%s)
  sleep_seconds=$(( $target_epoch - $current_epoch ))

  sleep $sleep_seconds
}

target_time="11:59"; sleepuntil $target_time