Re: writing binary data

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Date:         Mon, 29 Mar 2004 06:41:25 -0500
To: aix-l@Princeton.EDU

Holger,

I created the following script (called it "hex1"):

- - - - - snip - - - - -
#!/bin/sh

    STRING="80DF000038600002540807FE38A00000"

    P1=1; P2=2

    HEX=$(echo $STRING | cut -c${P1}-${P2})

    while [[ -n $HEX ]]; do

        OCT=$(echo "ibase=16\nobase=8\n$HEX" | bc)

        echo "\0${OCT}\c"

        P1=$((P1+2)); P2=$((P2+2))

        HEX=$(echo $STRING | cut -c${P1}-${P2})

    done
- - - - - snip - - - - -

And ran it as follows:

->sh hex1 >out1

Now when I run od on the output:

-> od -x out1
0000000 80df 0000 3860 0002 5408 07fe 38a0 0000
0000020

Bill Thompson
Sr UNIX Systems Administrator
The Goodyear Tire & Rubber Co.

Contains Confidential and/or Proprietary Information
May Not Be Copied or Disseminated Without Express Consent of The Goodyear Tire & Rubber Company.

AIX-L Archives: http://marc.theaimsgroup.com/?l=aix-l&r=1&w=2

----- Original Message -----
From: "Jean-Marc Monnez" <monnez.jean-marc@AGORA.MSA.FR>
Newsgroups: bit.listserv.aix-l
To: <aix-l@Princeton.EDU>
Sent: Monday, March 29, 2004 4:52 AM
Subject: Re: writing binary data

The escape you need in echo or print is \0 followed by the octal value
of the byte.
F.e. to add 80 (hex), use 200 (octal).
echo "\0200\c" > binfile

Your main work is octal conversion for each byte....

Regards

-- JMM

-----------------------------
Jean-Marc MONNEZ
MSA / AGORA / ATD
monnez.jean-marc@agora.msa.fr
-----------------------------

Holger.VanKoll@SWISSCOM.COM a écrit :

> Hello Aix-lers,
>
> I have this string
>
> 80DF000038600002540807FE38A00000
>
> containing 16 bytes ( 80 , DF , 00, 00 and so on).
>
> I want to have a binary file containg those bytes.
> So that
> cat file|od -x
> would give this output:
>
> 0000000 80DF 0000 3860 0002 5408 07FE 38A0 0000
>
> I could use cut to get every single byte; f.e.
>
> echo 80DF000038600002540807FE38A00000|cut -c1-2
> echo 80DF000038600002540807FE38A00000|cut -c3-4
>
> and I also know how to convert those bytes to decimal, if necessary.
>
> I just see no way to write binary data.
> If $a contains 80 (hex) or 128 (decimal), a echo $a >filename just
> creates a textfile with 128.
>
> Any suggestions?
>
> Regards,
>
> Holger

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