Working with variables in an exiftool call

[philbond87]

I have an application that iterates through a directory of DNG files and makes individual exiftool calls to extract an embedded image and save it out as a JPG file, with the same root filename as the DNG.

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"usr/local/bin/exiftool -b -PreviewImage " + dng.shellPath + " >" + destinationFolder.shellPath + "/" + filename
(I construct the destination

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filename in code)

This works great but I suspect it would be significantly faster if I could make one exiftool call on the entire directory, but I don't know how I can construct a the proper filename for each file the exiftool call will encounter in the directory.

How would this be done?

[StarGeek]

This example in the docs would be a good place to start.  It uses the -W (-TagOut) option to extract all the preview images in the file, writing each to a separate file.  The various percent tokens detailed in the -w (-TextOut) option can be used to give you some control over the output filename if it's based upon the original filename in any way.

[philbond87]

@StarGeek
Brilliant. Tremendously helpful.
Thank you!