Exiv2

Hi Günter,

You may have to look for a more generic UNIX list to get an answer for that question. I don't think the observed (mis)behaviour has anything to do with exiv2.

As a workaround you could try with an explicit loop instead, something like

for i in `find . -name '*.tif'` ; do exiv2 -M "set Exif.Image.DocumentName `zbarimg -q -Sdisable -Sqrcode.enable --raw $i`" $i ; done

Andreas

Hi Günter

I agree with Andreas that this is a UNIX shell puzzle and unlikely to be anything wrong with exiv2. The command echo isn't the best way to diagnose this stuff. I have a tiny utility "args" (for which I've posted the code below) which I find very useful for debugging this kind of issue.

You'll notice that
$ echo how now brown cow
and
$ echo "how now brown cow"
produce identical output in the terminal, however args is much more illuminating:

529 /Users/rmills/clanmills $ args how now brown cow
0 : args
1 : how
2 : now
3 : brown
4 : cow
530 /Users/rmills/clanmills $ args "how now brown cow"
0 : args
1 : how now brown cow
531 /Users/rmills/clanmills $

I'm also a little surprised that you use -exec sh -c bla bla in your find command. I always simply use -exec exiv2 bla dee bla etc... However I don't think that's the issue here as my suspicion is that your `....` stuff is broken into many little arguments.

// args.cpp
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char print(unsigned char c)
{
    return ( 32 <= c && c <= 127 ) ? c : '?' ;
}

int main(int argc, char* argv[])
{
    int i = 0 ;

    while ( i < argc ) {
        printf("%-2d: %s\n",i,argv[i]) ;
        i++ ;
    }
    return 0 ;
}

Many thanks Robin for your input and this very helpful little tool. I used it for some testing and found out that my above stated one-liner is doing well for all images containg a qrcode. But the zbarimg command part is not providing a result on images not conatining a qrcode. In those cases the final parameter for exiv2 remains NULL and exiv2 is complaining this. It seems like exiv2 is unable to set the content of a tag to "" (NULL) or " " (SPACE). The error I mentioned in my first post was then thrown just for such images.
I would have never found this without your support.
Just for the records (and if someone should evre stumble about a similar prob) I have updated my one-liner to make shure that it works with all images by adding one additional character like this:

find . -name '*.tif' -exec sh -c 'args -M "set Exif.Image.DocumentName `zbarimg -q -Sdisable -Sqrcode.enable --raw {} & echo -n "_"`" {}' \;

again
THX and kind regards

Although not completely perfect, this is a solution I can live with, but will continue to search if I can convince exiv2 to accept a one-space-character as a tag content.

$ ./exiv2 -M'set Exif.Image.DocumentName ""' exiv2-empty.jpg
$ ./exiv2 -pa exiv2-empty.jpg 
Exif.Image.DocumentName                      Ascii       0  

And the winner is:

find . -name '*.tif' -exec sh -c 'exiv2 -M "set Exif.Image.DocumentName \"`zbarimg -q -Sdisable -Sqrcode.enable --raw {}`\"" {}' \;

This one is exactly doing what I was looking for!

I do thank you both Robin & Andreas

Hi,
Here are some tutorials about barcode reading processing I found by Google:
http://www.pqscan.com/read-barcode/barcode-csharp.html
http://www.pqscan.com/read-barcode/
I hope it helps. Good luck.

Best regards,
Pan