Shell Script - Interactive Calculator

Script : Interactive Calculator

Script Name: calculator.sh

Script Function:Script to run a fully interactive command line–based calculator.

Script Usage: ./calculator.sh

Code:

#!/bin/bash
# calc--A command line calculator that acts as a frontend to bc
scale=2

scriptbc(){
if [ "$1" = "-p" ] ; then
        precision=$2
        shift 2
else
        precision=2 # Default
fi
bc -q -l << EOF
scale=$precision
$*
quit
EOF
}

show_help()
{
cat << EOF
In addition to standard math functions, calc also supports:
a % b remainder of a/b
a ^ b exponential: a raised to the b power
s(x) sine of x, x in radians
c(x) cosine of x, x in radians
a(x) arctangent of x, in radians
l(x) natural log of x
e(x) exponential log of raising e to the x
j(n,x) Bessel function of integer order n of x
scale N show N fractional digits (default = 2)
EOF
}
echo "Calc--a simple calculator. Enter 'help' for help, 'quit' to quit."
/bin/echo -n "calc> "
while read command args
do
        case $command
        in
                quit|exit) exit 0 ;;
                help|\?) show_help ;;
                scale) scale=$args ;;
                *) scriptbc -p $scale "$command" "$args" ;;
        esac
        /bin/echo -n "calc> "
done
echo ""

exit 0