Using unshift and splice in a loop will do the trick in this special case as we are not changing the size of the array so the subscript isn't mucked up.

$ perl -E '
> @arr = qw{ apple ball cat dog elephant fish dog budgie };
> for ( 1 .. $#arr )
> {
>     unshift @arr, splice @arr, $_, 1 if $arr[ $_ ] eq q{dog};
> }
> say for @arr;'
dog
dog
apple
ball
cat
elephant
fish
budgie
$
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I hope this is helpful.

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