Working with HEX in scripts

[Mike Rightmire]

Hey!
I am trying to write a simple script which determines a free node number for use with the mknode command. The real question is, how do I work with hex numbers in shell scripts there must be a simply way (other than writing a conversion in the script.)

Very simply I need to count in hex and not decimal. I need to be able to add 5 + 5 and come up with A (not ten) and add another 5 to it and come up with F, ETC.

Thanks for the help. I am sure this is a simple question with a simple command, but I don't know what it is :-)

Mike

[Patrick Wallek]

Have a look at 'dc'. I don't know if this'll do what you want or not, but here's the man page on it.

http://docs.hp.com/hpux/onlinedocs/B2355-90680/B2355-90680.html

[A. Clay Stephenson]

Hi Mike:

My utility of choice would be bc.

e.g.
bc
obase=16 # sets output base to hex
5 + 5 # add 5 decimal + 5 decimal
A
quit

You will have problems doing a running total because A + 5 in decimal ibase is an error; you could do all input in hex to solve that by specifying ibase=16 as well.

The other simple answer is to create a small script to simply do decimal to hex conversion:

#!/usr/bin/sh

while [ $# -ge 1 ]
do
echo "obase=16;${1};quit" | bc
shift
done


you would then execute my.sh 10 20
to output:
A
14

Another variation:

X="0"
while [ -n "${X}" ]
do
echo "Enter decimal value ( to quit): \c"
read X
if [ -n "${X}" ]
then
echo "Hex: \c"
echo "obase=16;${X};quit" | bc
fi
done

Man bc for details.

Clay

[James R. Ferguson · Accepted solution]

Hi Mike:

Another way is to do your arithmetic in decimal and let the 'printf' function convert decimal to hexadecimal, as:

#!/usr/bin/sh
let N=5+5+5
printf "%#s %#x\n" "N =" $N

Regards!

...JRF...

[linuxfan]

Hi Mike,


You could try something like this

MINOR=$(ls -l /dev/*/group | awk ' {print $6}' | sed "s/0x//;s/0000$//" | sort |tail -1)

MINOR=$(echo "obase=16;$MINOR+1;quit"|bc)

MINOR=0x0${MINOR}0000

echo "The new minor number is $MINOR"

-HTH
Ramesh

[Carlos Fernandez Riera]

For ksh

#! /usr/bin/ksh

let dec=16#1F
echo $dec
printf "%d , %x \n" $dec $dec



Am i a wizard or not?

[Robin Wakefield]

Hi Mike,

...and using let/typeset:

================================
#!/bin/ksh
typeset -i16 z
while [ $# -ne 0 ] ; do
let z=z+16#$1
shift
done
echo $z | cut -d# -f2
================================

# ./myscript.ksh e 5 a
1d

Rgds, Robin

[Mike Rightmire]

Hey Gang!

Thanks for all the help. The final script was too long to place here, but it ended up being a combination of James' printf commands and Ramesh's script.

Thanks again for all the help!
Mike