bc and its ibase/obase options:

Question

I stumbled over a curious bug, I think:

I tried to read \"512\" as a number to base 6, and output it as base 16:

echo \"ibase=6;obase=16;512\" | bc
161         


        

Answer 1

Slightly modify the code (two ways) and your expected results appear:

for ib in {6,8,10,16}; do 
    echo $ib; for ob in {10,16}; do 
        echo -en $ib $ob"     \t => " ; 
        ob=`echo "obase=$ib;$ob" | bc`
        echo "ibase=$ib;obase=$ob;333" | bc ; 
    done; 
done;

for ib in {6,8,10,16}; do 
    echo $ib; for ob in {10,16}; do 
        echo -en $ib $ob"     \t => " ; 
        echo "obase=$ob;ibase=$ib;333" | bc ; 
    done; 
done;

execute in bash sandbox

results for both ways are:

6
6 10         => 129
6 16         => 81
8
8 10         => 219
8 16         => DB
10
10 10        => 333
10 16        => 14D
16
16 10        => 819
16 16        => 333