Notes on exiftool

Introduction

These are my notes on using exiftool to organize a jumbled mess of digital images. This is written more as a personal memory jogger, unlikely to be of value to anyone else.

General

Before getting to exiftool, here are a couple of handy one-liners.

Print all of the file extensions present in $DIR, one per line:

find "$DIR" -type f | sed -e 's/.*\.//' | sed -e 's/.*\///' \
     | sort -u

Print all of the file extensions present in $DIR, one per line, along

with a count of the number of files with that extension:

find "$DIR" -type f | sed -e 's/.*\.//' | sed -e 's/.*\///' \
     | sort | uniq -c | sort -rn

Organizing Photos Based on Date

If a photo's ultimate location will be based in some way on a date, the date to be used in determining the location will have to come from somewhere. The most obvious approach is to use one of the dates that should be present in the photo's EXIF data. I use DateTimeOriginal, which is the date on which an image was taken -- either by a traditional film camera or a digital camera.

CreatDate is subtly different -- it is the date that the digital image was created. This is either the date that a digital photo was taken or the date that a traditional photo was scanned.

Unfortunately, not all images will have a DateTimeOriginal or even a CreateDate. Therefore, before we can reorganize, our first step is to ensure that each image has a valid DateTimeOriginal.

exiftool -r -if '(not $DateTimeOriginal)'             \
            '-DateTimeOriginal<MDItemFSCreationDate'  \
            '-DateTimeOriginal<GPSDateTime'           \
            '-DateTimeOriginal<CreateDate'            \
            "$PHOTODIR"

exiftool -r -if '($FileModifyDate lt $DateTimeOriginal)' \
            '-DateTimeOriginal<FileModifyDate'           \
            "$PHOTODIR"

find "$PHOTODIR" -name \*_original -delete

Harmonizing File Extensions

Often, a single image type may be present with different file name extensions. E.g., one may have photos ending in both .jpg and .jpeg. I chose to enforce consistent entensions.

The following command will convert .jpeg to .jpg. We'll ignore case conversion for the moment, because my macOS is configured to be case insensitive.

exiftool -r -filename=%f.jpg -ext jpeg "$PHOTODIR"

If you have a case sensitive filesystem, the following would take care of both changing jpeg to jpg and lowercasing and uppercase extensions:

exiftool -r -filename=%f.jpg -ext jpg -ext jpeg \
            -if '$filename!~/\.jpg$$/' "$PHOTODIR"

exiftool can be used to do this, but there are other tool (e.g., find, the Perl rename module) that will likely be much faster if extension renaming is your only goal.

Reorganize

These examples will reorganize photos by placing copies of the originals into a new directory structure with the following overall format: new/ext/yyyy/mm/dd/hh/file.ext. It's not difficult to move rather than copy. Note that DateTimeOriginal, which we set earlier, is used to determine the directory structure for each image.

Notice that some of the parameters in the expression supplied to '-d' require two '%' signs, one which escapes the other. Also note the use of %le, which will convert a file extension to lowercase, if necessary. See <http://owl.phy.queensu.ca/~phil/exiftool/filename.html>.

If you'd like to try a dryrun before doing anything, the following invocation only prints what it would do to stdout -- it does not actually copy, move, rename, or otherwise modify the filesystem.

exiftool -r '-testname<DateTimeOriginal' \
         -d 'new/%%le/%Y/%m/%d/%H/%%f%%-c.%%le' "$PHOTODIR"

This command will actually reorganize things:

exiftool -r '-filename<DateTimeOriginal' \
         -d 'new/%%le/%Y/%m/%d/%H/%%f%%-8c.%%le' "$PHOTODIR"

A new structure containing copies of the original photos will be created in ./new.

Be sure to check in both the new and original directories for any files that were left behind due to exiftool errors.

Other Invocations

1. Make a copy of all images in the directory ./SRC and place them in the directory ./DEST, maintaining the subdirectory structure.

   exiftool -r -o . -directory=DEST/%d SRC
   

   The -o . option sets the directory to ./ and also forces copies of the images to be made, rather than changing them in place. This directory setting is subsequently overridden by the -directory= option, which sets the output directory to ./DEST with the relative path of the image under ./SRC appended.

   E.g., the original image ./SRC/foo/bar/baz.jpg is copied to ./DEST/SRC/foo/bar/baz.jpg. I'm sure there's a way to remove the unnecessary SRC subdirectory in the output, but I haven't attempted to determine how to to this.

   To better understand how this works, consider another example.

   exiftool -r -o . -directory=DEST/%d `pwd`/SRC
   

   This has a different result than the previous example. The fully qualified path is used for the subdirectory structure under ./DEST. If $PWD is /Users/khe/example, then the original image ./SRC/foo/bar/baz.jpg will be copied to ./DEST/Users/khe/example/SRC/foo/bar/baz.jpg.

2. Find all duplicate files, where duplicate is defined as a file name containing '-nnnnnnnn' (a dash followed by eight digits) preceding the three character extension.

   exiftool -r -FileName -if '$FileName =~ /[0-9]{8}\..../'
            dupes/src-new/jpg/1970
   

3. Get image sizes info.

   # dimensions of every image
   exiftool -r -T -progress: -imagesize -directory \
            -filename  photos > sizes.all
   
   # counts of image sizes, ordered by frequency
   sed 's/x/ /' < sizes.all                             \
       | awk '{printf "%12d %6d %6d\n", $1*$2, $1, $2}' \
       | sort -n | uniq -c | sort -n > sizes.frequency
   
   # counts of image sizes, ordered by image size
   sort -n -k 2 sizes.frequency > sizes.size
   

4. exiftool processing based on image size/dimensions.

   # images less than 256x512 in size
   exiftool -if '$imagesize and ($imagewidth<256 and $imageheight<512)' \
            -filename -r -T src-new