#!/usr/bin/perl

%num2mon = qw(
        01      Jan
        02      Feb
        03      Mar
        04      Apr
        05      May
        06      Jun
        07      Jul
        08      Aug
        09      Sep
        10      Oct
        11      Nov
        12      Dec
);
open (THIS, "this") ||
        die "can't open file $!";

foreach ($i in <THIS>);
s/\[(..)h:(..)m:(..)s_(..)\/(..)\/(..)\](.+)/"$num2mon{$4} $5 $1:$2:$3 $7"/eg
write;

close (THIS);