my $yen = <STDIN>;
[download]

Now the "\r?\n" is still attached to the contents of the variable $yen. You want to say

chomp(my $yen = <STDIN>);
[download]

See chomp and chop.

<update>

See also perlvar for $/.

</update>

--shmem

update: changed "\n" to "\r?\n" above, and /s/chop/chomp/, since chop chops one character, while chomp removes a trailing $/ (which might be "\r\n" or "\r". Thanks to ikegami for telling me in a /msg.

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}