First a remark: 1110 1111 is not a hexadecimal number, it is in binary and it is not even the binary representation of 254, which is 11111110 (254 is even, so its rightmost bit cannot be 1).

Taking that into account, the following will do what you want:

use strict;

my $debug = 1;
my $dec= 254;
print "$dec\n";
print shift_left($dec) ;

sub dec2bin {
    my $str = unpack("B32", pack("N", shift));
    $str =~ s/^0+(?=\d)//;   # otherwise you'll get leading zeros
    print "$str\n" if $debug;
    return $str;
}

sub bin2dec {
    return unpack("N", pack("B32", substr("0" x 32 . shift, -32)));
}

sub shift_left {
    my $bin_reversed = reverse dec2bin(shift);
    chop $bin_reversed;
    print ' ' . reverse ($bin_reversed) . '0' . "\n" if $debug;
    return bin2dec(reverse ($bin_reversed) . '0');
}
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Output:

254
11111110
 11111100
252
[download]

The bin2dec and dec2bin routines are from the Perl Cookbook (recipe 2.4).