repeats a command as long as its execution is more than 3 seconds

repeater.sh

#!/bin/bash

while [[ true ]]; do
    echo "[`date`] Repeating $1"
    START=`date +%s`
    $1
    END=`date +%s`

    DURATION=`echo "$END-$START" | bc`

    if [[ $DURATION -lt 3 ]]; then
        echo "Command $1 run for less than 3 seconds. Aborting."
        exit
    fi
done