function decToHex()
{
DEC=${1?You should provide an argument}
echo $DEC|grep -q -E "^[0-9]+$" || { echo "The argument is not a decimal"; return 1 ; }
printf "%x\n" ${DEC}
}
function hexToDec()
{
HEX=${1?You should provide an argument}
echo $HEX|grep -q -E "^[0-9a-fA-F]+$" || { echo "The argument is not a hexadecimal"; return 1 ; }
printf "%d\n" 0x${HEX}
}
A few examples
safeer@penguinpower:~$ decToHex 10
a
safeer@penguinpower:~$ hexToDec a
10
safeer@penguinpower:~$ decToHex 1234
4d2
safeer@penguinpower:~$ hexToDec abc
2748