stopwatch or countdown

gistfile1.txt

countdown() {
    [[ -z $1 ]] && seconds=60 || seconds=$1
    since=$(date +%s)
    remaining=$seconds
    while (( remaining >= 0 ))
    do
        printf "\r%-10d" $remaining
        sleep 0.5
        remaining=$(( seconds - $(date +%s) + since ))
    done
    $2   # can specify a command to do at the end of the countdown
    # for instance:    countdown 3 lt
    # or:    countdown 3 'lt mar'
}