#!/bin/sh
# oct2dec --  octal to decimal conversion.
#

(O=$1;o=400;d=256;until [ $d = 0 ]; do { d=$[$d/2];o=$[$o/2];[ $o = 5 ]&&o=4;[ $o = 50 ]&&o=40;[ $[$O-$o] -ge 0 ]&&{ O=$[$O-$o];D=$[$D+$d]; }; };done;echo $D)
