This is a simple calculator that reads postfix expressions from stdin and process them on a stack. Whenever a newline character is read, the top of the stack is printed to stdout.

Building and installing:

$ make
$ sudo make install

Examples:

$ echo "2 3 +" | rad
5
$ echo "60 60 24 7 * * *" | rad
604800
$ echo "5 sqrt 1 - 2 /" | rad
0.61803399
$ printf "5 sqrt\n1 -\n2 /\n" | rad
2.236068
1.236068
0.61803399
$ rad
5 sqrt
2.236068
1 -
1.236068
2 /
0.61803399
$

Rad has support for bitwise operations, trigonometry, complex number arithmetic and some basic number theoretic functions. See the man page for a complete list of supported operations.