Script for dumping the time difference between a bunch of log lines.

delta_t.rb

#!/usr/bin/env ruby
require 'time'

# USAGE: This takes a bunch of lines as input, looks for dates, sorts them and
# then outputs the difference between the smallest and largest.
#
#   pbpaste | ruby delta-t
#   tail -f log/development.log | ruby delta-t
#
# TODO:
# - Add more time formats
# - Better output formatting

# EXAMPLE: 15:07:24 2017-01-20
TIMESTAMP_PATTERN = /\d{2}:\d{2}:\d{2} \d{4}-\d{2}-\d{2}/

ARGF.readlines
  .map { |line| line[TIMESTAMP_PATTERN] }.compact
  .map { |timestamp| Time.parse(timestamp) }
  .sort
  .minmax
  .tap { |min, max|
    total = max - min
    minutes = total / 60
    seconds = total % 60

    puts format('%02d:%02d', minutes, seconds)
  }