RRFcalc reads input a line at a time and treats it as commands for a calculator working in Reverse Polish Notation. It is convenient for interactive use, but it can be used noninteractively by supplying a file of commands as standard input.
After each line of input has been processed, the top item on the stack is displayed, unless the last command already displayed it. The commands available are:
integer  read the integer (which must be nonnegative) and put it on the stack. To get a negative number on the stack, you need to read in a positive number and use CHS to change the sign. 
PP rrf  read the rest of the line as a rootrationalfraction in powerofprime form, and put it on the stack. 
+  Add: replace the top two elements on the stack by their sum. 
  Subtract (topofstack from the one below). To change the sign of the topofstack, use CHS. 
*  Multiply 
/  Divide (topofstack into the one below) 
POWER n  raise to power n (n = integer or integer/2). 
SQRT  = POWER 1/2. Note that it is an error to take the square root of a number which already contains halfoddinteger powers. 
CHS  change sign 
SWOP, SWAP  exchange top two items of stack 
STO n  Store topofstack in memory n (1 ≤ n ≤ 25). The item is not removed from the stack. 
RCL n  Recall from memory n to topofstack. 
V  Verify top of stack. 
LIST  List the entire stack using the current default verification mode. Top of stack is shown first. 
VP  Verify topofstack in powerofprime notation 
VI  Verify topofstack as (a/b)*sqrt(c/d), where a, b, c and d are integers (standard default). 
VF  Verify topofstack as a floatingpoint number. 
VMP  Change default verification mode to powerofprime. 
VMI  Change default verification mode to (a/b)*sqrt(c/d). This is the usual default. 
VMF  Change default verification mode to floatingpoint. 
0J, 3J, 6J, 9J  Calculate a Wigner 3j, 6j or 9j symbol and put it on the stack. 0J
calculates a 3j symbol for which all m values are zero. The full input
for these commands takes the form:

POP  Delete the top member from the stack. 
PUSH  Push the stack down, copying the top member. PUSHing an empty stack inserts zero. 
CLR,CLEAR  Clear the stack. 
PROMPT ‘string’  Set prompt string. The string is output when the program is ready for the next line of commands. The default string is ‘:’. A null string may be set. 
ECHO+  Reflect each input line before obeying any commands. 
ECHO  Do not reflect input lines (default). 
(  Ignore rest of line. 
?  Give a summary of the available commands. 
QUIT, Q  Quit. 