Almut's solution is good, but not scalable. If you use a hash, you can easily add more dates in the future.

my %DATES = (
    "7/Jun/2010:23:02:10 " => "2010061802:00:14",
    "7/Zog/2100:12:63:13 " => "2010060608:39:11",
    "my birthday"          => "1974012618:12:10",
    #simply add all the other dates to this hash!
);

sub convert {
    return $DATES{$_[0]}
}
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