use POSIX;

my $filename = strftime( "%Y%m%d%H%M%S.log", localtime );
print "lets open a file called $filename ...\n";
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Personally, I like to throw in a little punctuation, because it's easier to look at, and it can be easier to grep for a given day or a given hour:

  strftime( "%Y%m%d_%H%M%S.log", localtime );
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