language.txt

From Wikipedia:

0-9	Push this number on the stack
+	Addition: Pop a and b, then push a+b
-	Subtraction: Pop a and b, then push b-a
*	Multiplication: Pop a and b, then push a*b
/	Integer division: Pop a and b, then push b/a, rounded towards 0.
%	Modulo: Pop a and b, then push the remainder of the integer division of b/a.
!	Logical NOT: Pop a value. If the value is zero, push 1; otherwise, push zero.
`	Greater than: Pop a and b, then push 1 if b>a, otherwise zero.
>	Start moving right
<	Start moving left
^	Start moving up
v	Start moving down
?	Start moving in a random cardinal direction
_	Pop a value; move right if value=0, left otherwise
|	Pop a value; move down if value=0, up otherwise
"	Start string mode: push each character's ASCII value all the way up to the next "
:	Duplicate value on top of the stack
\	Swap two values on top of the stack
$	Pop value from the stack and discard it
.	Pop value and output as an integer followed by a space
,	Pop value and output as ASCII character
#	Bridge: Skip next cell
p	A "put" call (a way to store a value for later use). Pop y, x, and v, then change the character at (x,y) in the program to the character with ASCII value v
g	A "get" call (a way to retrieve data in storage). Pop y and x, then push ASCII value of the character at that position in the program
&	Ask user for a number and push it
~	Ask user for a character and push its ASCII value
@	End program