simple stopwatch in bash

stopwatch.sh

# add to your ~/.bashrc

function stopwatch() {
  local BEGIN=$(date +%s)

  while true; do
    local NOW=$(date +%s)
    local DIFF=$(($NOW - $BEGIN))
    local MINS=$(($DIFF / 60 % 60))
    local SECS=$(($DIFF % 60))
    local HOURS=$(($DIFF / 3600 % 24))
    local DAYS=$(($DIFF / 86400))
    local DAYS_UNIT
    [ "$DAYS" == 1 ] && DAYS_UNIT="Day" || DAYS_UNIT="Days"

    printf "\r  %d %s, %02d:%02d:%02d  " $DAYS $DAYS_UNIT $HOURS $MINS $SECS
    sleep 0.25
  done
}