calc

#!/bin/bash

help() {
	echo "Usage: calc expression"
	echo "Use awk for arithemetic operations"
	echo
	echo "Operations: "
	echo
	echo "    x + y       Addition"
	echo "    x - y       Subtraction"
	echo "    - x         Negation"
	echo "    x * y       Multiplication"
	echo "    x / y       Division"
	echo "    x % y       Modulo"
	echo "    x ^ y       Exponentiation"
	echo "    int(x)      Truncate integer toward zero"
	echo "    sqrt(x)     Positive square root"
	echo "    exp(x)      Exponentiation e ^ x"
	echo "    log(x)      Natural logarithm"
	echo "    sin(x)      Sine (in radians)"
	echo "    cos(x)      Cosine (in radians)"
	echo "    atan2(x, y) Arctangent of x / y (in radians)"
	echo "    rand()      Random number between zero and one"
	echo "    srand(x)    Random number starting at x"
	echo
	exit 1
}

[ "$1" == "--help" ] && help

awk "BEGIN{print $1}"