Hex2dec

<highlightSyntax>

1. !/bin/bash
2. hex to decimal number converter
3. mutante (s23.org) 11/2006

read -p "Give me a hex number " hex length=${#hex} i=0 result=0 let length-- pos=0 while [ $length -ge 0 ]; do

 digit=${hex:$length:1}

 case "$digit" in
  A | a) ddigit=10;;
  B | b) ddigit=11;;
  C | c) ddigit=12;;
  D | d) ddigit=13;;
  E | e) ddigit=14;;
  F | f) ddigit=15;;
  [0-9]) ddigit=$digit;;
      *) echo "Bad input. Only 0-9 and a-f are allowed."; exit 1;;
 esac

factor=`echo "(16^$pos)" | bc`
subresult=`echo "$factor*$ddigit" | bc`
echo "[$pos]: $digit = $ddigit * (16^$pos) = $ddigit * $factor = $subresult"
let result=$result+$subresult
let pos++
let length--

done

echo "Result: $hex (hex) is $result (dec)" | boxes exit 0 </highlightSyntax>

 ./hex2dec.sh

Give me a hex number 523F
[0]: F = 15 * (16^0) = 15 * 1 = 15
[1]: 3 = 3 * (16^1) = 3 * 16 = 48
[2]: 2 = 2 * (16^2) = 2 * 256 = 512
[3]: 5 = 5 * (16^3) = 5 * 4096 = 20480
/*************************************/
/* Result: 523F (hex) is 21055 (dec) */
/*************************************/