If you read the documentation, you'll see that oct is capable of conversion from binary.  It just requires putting a leading '0b' in front of the number.

For example:

use strict;
use warnings;

my $value = "0b101010";
printf "$value is %d decimal\n", oct($value);
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Not too long ago, I even wrote a submission about it, in which I admitted that I didn't know about this additional functionality of oct until much later in my Perl education.

As for your other question, to make links clickable, you can do this:  [id://591504], which will appear like "Bitwise operators" in the rendered page.

See Writeup Formatting Tips and Perl Monks Approved HTML tags for more information.

Update:  Fixed a transcription typo.