octave, 185 bytes

Result [link]

WA

Code [DL]

s = fileread(num2str(getppid(), "/proc/%d/fd/0"));

dec = 0;

for i = (1:length(s))
	if (s(i) == "1")
  		dec = 2 * dec + 1;
	else
  		dec = 2 * dec;
	endif

endfor

disp (num2str(dec))

stdin

1101001111101011000101101110010010010011110011111000010011010011001000000001010001011001010001111000

stdout

1049368683975750266819201466368

stderr

strace