hex

#!/bin/bash
## hexadecimal conversion

if [ $# = 0 ]; then
    echo "Usage :hex [0x]number[b]"
    echo "number could be hexadecimal(0x),binary(b),or decimal(default)"
    exit 0;
fi
input=$1
echo $input | grep -q "^0x" 
if [ $? = 0 ];then
    hex_number=$input
    dec_number=$(($input))
    binary_number=`echo "obase=2;$dec_number"|bc`
fi
echo $input | grep -q "b$"
if [ $? = 0 ]; then
    binary_number=`echo $input |cut -c1-$((${#input}-1))`
    dec_number=$((2#$binary_number))
    hex_number=`printf "%x" $dec_number`
fi

if [ "$dec_number" = "" ]; then
    dec_number=$input
    hex_number=`printf "%x" $dec_number`
    binary_number=`echo "obase=2;$dec_number"|bc`
fi
echo "2 : "$binary_number"b"
echo "10: "$dec_number
echo "16: "$hex_number