Shell Script 024-calc.sh

#!/bin/sh

# calc - a command-line calculator that acts as a front-end to bc

scale=2

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, returns 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
}

if [ $# -gt 0 ] ; then
  exec scriptbc "$@"
fi

echo "Calc - a simple calculator. Use 'help' for help, 'quit' to quit."

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

  echo -n "calc> "
done

echo ""

exit 0