echo "cbaab" | tr abc zyx > logfile.gnu
echo "TESTING A B C" | tr [A-Z] [a-z] >> logfile.gnu
echo abc[] | tr a[b AXB >> logfile.gnu

echo "cbaab" | busybox tr abc zyx > logfile.bb
echo "TESTING A B C" | busybox tr [A-Z] [a-z] >> logfile.bb
echo abc[] | busybox tr a[b AXB >> logfile.bb

cmp logfile.gnu logfile.bb