#!/usr/bin/env perl
# $Id: iso8601ify-dates,v 1.1 2019/07/03 22:22:36 friedman Exp $

# Filter to convert text of the form "MMM [d]d yyyy" to "yyyy-mm-dd".
# No, this isn't locale-aware in any way.

$i = 1;
%m = map { $_ => $i++ } (qw(jan feb mar apr may jun jul aug sep oct nov dec));
$p = join('|', keys %m);

while (<>)
  {
    s=\b($p)\s+(\d{1,2})\s+(\d{4})\b=sprintf("%04d-%02d-%02d",$3,$m{lc $1},$2)=egio;
    print;
  }

# eof