stopwatch with laps for bash #bash

stopwatch.sh

#!/bin/bash

function stopwatch() {
  local n=0
  local t=0
  local continuing="true"
  local lap=1
  local key="~"
  local pausing="~"

  cat <<EOF

  * type "p" to pause and "r" to resume
  * hit the spacebar to start a new lap
    * if paused you will resume with a new lap
  * type "q" or "x" or Ctrl-c to stop

EOF

  function summary() {
    continuing="false" # break the while loop
    local elapsed=$(($t-$lap+1))
    printf "\r\033[0KLap ${lap}: $n seconds\n"
    printf "\nTotal Elapsed: $elapsed seconds\n"
  }

  trap "summary" SIGINT

  while [[ $continuing = "true" ]]; do
    key="~"
    pausing="~"
    printf "\r\033[0KLap ${lap}: $n seconds"
    read -s -t 1 -n 1 key

    case "$key" in
      "")
        printf "\r\033[0KLap ${lap}: $n seconds\n"
        key=""
        n=-1
        ((lap++))
        ;;
      q|x)
        summary
        break
        ;;
      p)
        function paused() {
          read -s -n 1 pausing
          case "$pausing" in
            "")
              printf "\r\033[0KLap ${lap}: $n seconds\n"
              key=""
              n=-1
              ((lap++))
              ;;
            q|x)
              summary
              break
              ;;
            r)
              : # noop
              ;;
            *)
              paused
              ;;
          esac
        }
        paused
        ;;
    esac
    ((t++))
    ((n++))
  done
}