Example 1:

sub timestamp {
  return localtime (time);
}

print '[' . timestamp() . ']: Normal Time Format'. "\n";
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Output 1:

[Sat Jan  8 11:59:07 2011]: Normal Time Format
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Example 2:

use Time::localtime;
sub timestamp {
  my $t = localtime;
  return sprintf( "%04d-%02d-%02d_%02d:%02d:%02d",
                  $t->year + 1900, $t->mon + 1, $t->mday,
                  $t->hour, $t->min, $t->sec );
}

print '[' . timestamp() . ']: Custom Time Format'. "\n";
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Output 2:

[2011-01-08_12:06:05]: Custom Time Format
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