2

var good_records = 0;
var dates = Hash.new;
 
ARGF.each { |line|
    var m = /^(\d\d\d\d-\d\d-\d\d)((?:\h+\d+\.\d+\h+-?\d+){24})\s*$/.match(line);
    m || (warn "Bad format at line #{$.}"; next);
    dates{m[0]} := 0 ++;
    var i = 0;
    m[1].words.all{|n| i++.is_even || (n.to_num >= 1) } && ++good_records;
}
 
say "#{good_records} good records out of #{$.} total";
say 'Repeated timestamps:';
say dates.to_a.grep{ .value > 1 }.map { .key }.sort.join("\n");

Output:

$ sidef script.sf < readings.txt
5017 good records out of 5471 total
Repeated timestamps:
1990-03-25
1991-03-31
1992-03-29
1993-03-28
1995-03-26