You mean you want to decode url-encoded and the result happens to be in UTF-8 
while(<>) {
    print &urldecode($_);
}

sub urlencode {
    my $s = shift;
    $s =~ s/ /+/g;
    $s =~ s/([^A-Za-z0-9\+-])/sprintf("%%%02X", ord($1))/seg;
    return $s;
}

sub urldecode {
    my $s = shift;
    $s =~ s/\%([A-Fa-f0-9]{2})/pack('C', hex($1))/seg;
    $s =~ s/\+/ /g;
    return $s;
}

[download]
Produces from your input: об/стен

In reply to Re: To decode URL-decoded UTF-8 string. by TheloniusMonk
in thread To decode URL-decoded UTF-8 string. by nikolay

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