Re: bit string

Binary printf formats aren't supported in earlier versions. From v5.6.0 perldoc perldelta:

"Binary numbers supported

Binary numbers are now supported as literals, in s?printf formats, and `oct()':

$answer = 0b101010;
printf "The answer is: %b\n", oct("0b101010");"

Update: forgot to put in the meat.
As a string:

$ perl -e '$c = 12;print reverse map {vec $c,$_,1}  0..8*length($c)-1;
+'
0011001000110001
[download]

As a number:

$ perl -e '$c = 12;print reverse map {$c&1<<$_?1:0}  0..8;'
000001100
[download]

After Compline,
Zaxo

In Section Seekers of Perl Wisdom