Assign output to a variable within a for loop?

[Windvexer]

Hi all,

Brand new to ExifTool and not very well versed in Windows batch scripting, so please forgive this basic question. I'm trying to assign the output of am ExifTool command to a variable while inside a for loop and having no luck. I will ultimately be doing some basic arithmetic on each file's height and width values which I'll copy and paste into some HTML code, but I'm stuck just getting those values into a variable.

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@ECHO OFF
SETLOCAL ENABLEDELAYEDEXPANSION
for /r %%i in (*) do (
set imageWidth=exiftool -p $ImageWidth %%i
echo here it is !imageWidth!
)
PAUSE


Which outputs:

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here it is exiftool -p $ImageWidth C:\Users\jason\images\EasyMoney\forJason\chart1.png
here it is exiftool -p $ImageWidth C:\Users\jason\images\EasyMoney\forJason\chart2.png
here it is exiftool -p $ImageWidth C:\Users\jason\images\EasyMoney\forJason\chart3.png
here it is exiftool -p $ImageWidth C:\Users\jason\images\EasyMoney\forJason\chart4.png


Thanks in advance for any help,
WV

[StarGeek]

I'm not an expert in Windows batch files, but I believe you want the command in the parentheses.  Something like this StackOverflow answer.  I'm not sure what the exact command would be though.

But I would suggest that you try to let exiftool do most of the work, as calling exiftool in a loop like that can cause excessive delays because exiftool's biggest performance hit is the startup time (see Common Mistake #3).  For example, give exiftool the list of files/directories and redirect the output into a temp file if needed.  If you can let us know what the exact format you plan on copy/pasting is, then exiftool can probably output that format, saving you some time.

[Luuk2005]

Greetings, its hard to understand, so I make batch for you to study and to edit. It only does width, not height and also to be careful its not using -ext so ALL files with width in same folder gets the addition. Like StarGeek said, this very slow because exiftool must have to keep stopping and then start again.

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@echo off
SetLocal EnableDelayedExpansion
:: cd /d "Where TopFolder is Settled"
For /r %%A IN (.) DO (
For /f " delims=" %%B IN ('exiftool -p $ImageWidth "%%A" 2^>nul') DO (Set /a TotalWidth=TotalWidth+%%B)
echo TotalWidth for %%A:    !TotalWidth!)
pause>nul

Without edit, it makes the output like:
TotalWidth for C:\PathTo\Folder1.:    #####
TotalWidth for C:\PathTo\Folder2.:    #####
TotalWidth for C:\PathTo\Folder3.:    #####

[StarGeek]

Ah, so you're adding up the total width of all images in a directory.  Unfortunately, I don't know Windows batch that well.  And you seem to be getting all the files for each directory all at once, the only problem is it has to start up for each directory.

The only way I see for it to be quicker would be to run exiftool from the top most directory with the -r (-recurse) option, get the directory as well as the width, and then parse the output data, but that's more complex to do in a batch file than I can help with.

[Phil Harvey]

OK.  Here's a fun one...

With this a.args file:

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-r
-if
if ($filename eq 'end.jpg') { foreach my $$a (sort keys %$$myVar::sum) { print "TotalWidth for $$a: $$$$myVar::sum{$$a}\n" } } else { $$myVar::sum or $$myVar::sum={}; $$$$myVar::sum{$directory}=($$$$myVar::sum{$directory}||0)+$imagewidth } return 0;

and this command:

exiftool -@ a.args DIR end.jpg

You get an output like this:

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TotalWidth for ./tmp: 3354
TotalWidth for ./tmp2: 1442
    3 directories scanned
    8 files failed condition
    0 image files read

You just need to create a file named "end.jpg" in the current directory -- I'm using this as a trigger to print the output after all files are processed.

- Phil

[Luuk2005]

I make mistake in batch, because I forget to reset counter at each folder, it should be:

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@echo off
SetLocal EnableDelayedExpansion
:: cd /d "Where TopFolder is Settled"
For /r %%A IN (.) DO (
For /f " delims=" %%B IN ('exiftool -p $ImageWidth "%%A" 2^>nul') DO (Set /a TotalWidth=TotalWidth+%%B)
echo TotalWidth for %%A:    !TotalWidth!
set /a TotalWidth=0)
pause>nul

The batch is still very slow, so its much faster to do it like Mr Phil Havey with argfile, then exiftool only has to get started-up one time!
I must soon learn perl expressions, because I first try -r but cant invent way to output after each folder, even with using -execute.

[StarGeek]

Basically what Phil did was use exiftool as if you had installed Perl and ran straight Perl code from within exiftool.  Very tricky.

[Windvexer]

Thanks for the help, everyone. Looking forward to trying out these suggestions this weekend.