p -- print
n -- print and pop
P -- pop and print 
f -- print entire stack
+ -- pops 2 values of stack, adds them and pushes the result
-
*
/
%
~  div but both quotient and remainder are pushed
^
| exponentiation with base
v square root
c  clear stack
d  duplicate value on stack
r rev top 2 items on stack

sr  -- pop and store in reg r
lr  -- copy value in reg r and push to stack
Sr 
i pop and use it as input radix
o op the value of stack and use it as output radix

Hex to decimal conversion

HEX=41

echo 16iAo${HEX}p | dc
echo 16iAo${HEX}n | dc

print ascii character on inputting hex chr
printf "\x$HEX\n"

seq 1 1 26
nl
csplit
expand
comm
echo $((16/2))