my $pos;
for (0..$#array) {
    $pos=$_ and last
      if $array[$_] eq $wanted;
}
@array[$pos,-1]=@array[-1,$pos];
[download]

Update: it was a wonderfully neat solution (which is the reason why I posted it!) to another problem!!

Not just as neat:

my $pos;
for (0..$#array) {
    $pos=$_ and last
      if $array[$_] eq $wanted;
}
@array=@array[0..$pos-1, $pos+1..$#array, $pos];
[download]

And what if no one of them matched? (Left as an exercise to the reader ;-)

But then if you are sure in advance that one and only one element will match, here's a neat concise solution:

@array=((grep $_ ne $wanted, @array), $wanted);
[download]

@array = do {
    my $i;
    (grep $i || $_ ne $wanted || $i++, @array),
      $i ? $wanted : ();
};

# or, as a sub:

sub move {
    my ($wanted, $i)=shift;
    (grep $i || $_ ne $wanted || $i++, @_),
      $i ? $wanted : ();
}
[download]