use strict;
use warnings;
use POSIX q(strftime);

my @abc = ("a", "b", "c", "d", "e");

foreach (@abc) { print '[',(strftime '%Y-%m-%d-%H-%M-%S', localtime()).
                       "]\t$_\n"; sleep 1;}


#output
[2017-06-07-11-19-36]   a
[2017-06-07-11-19-37]   b
[2017-06-07-11-19-38]   c
[2017-06-07-11-19-39]   d
[2017-06-07-11-19-40]   e