Monday, June 06, 2022

How to find Mac OS tags from the command line

 I'm playing with tags for labeling photos and found this MacOs command to search for all files with a tag, like "awana":

mdfind 'kMDItemUserTags == "Awana"'

By the way macos tags are stored in the binary file '.DS_Store' in the same directory as your files, and as an Extended Attribute (EA) of the file.

Saturday, May 21, 2022

Fixing EXIF Errors in JPEG files like "Error: Bad format (0) for IFD1 entry 0"

I've been working on my greatgrandmother's photos and find jewels from 1910 like this one:

Unfortunately, many of the photos from 110 years ago do not have any names written on the back.

As I think about how to preserve my family's story for the next 110 or 300 years, I'd like to write the description on the back of my digital pictures by injecting EXIF image descriptions into the photos themselves.

To do this I downloaded the free command line tool "exiftool" for my mac.

Then, I added photo captions into jpeg files with this command:

exiftool -imageDescription="My image description" mypic.jpg

but got errors like this:

"Error: Bad format (0) for IFD1 entry 0"

I purchased the tool "metaImage" from the Mac store to add descriptions into the jpeg, but it wouldn't inject the caption into my files. I contacted their tech support and got a quick solution.

Jérémy Vizzini from (creator of "metaImage") solved the problem for me. The issue was my jpeg files were corrupt. (Some of the photos were from 2003, so the EXIF standards may have changed, or not have been rigoriously followed decades ago). Jérémy gave me this snippet of exiftool code to fix the jpeg:

  exiftool -all= -tagsfromfile @ -all:all -unsafe -icc_profile mypic.jpg

This fixed the problem. Thanks Jérémy! Now my jpegs will be ready for the next 300 years.

How do you archive your photos to preserve them for 300 years?

Wednesday, May 04, 2022

How to Find Duplicate Images on a Mac or Linux Machine

This is how to search recursively all directories on a Mac or Linux machine for duplicate images with a single line of awkward bash script. This method will find duplicates anywhere on your disk below your current directory (try "~"), and find multiple versions.

Many commercial products exist to easily find and delete duplicate images like those reviewed here, but if you are like me, and don't like to download apps willy nilly for a single task, and have a bit of shell scripting experience, you can use the following line of tortured bash script to find duplicate files.

find . -type f \( -name "*.jpg" -o -name "*.gif" \) | awk '{print "\"" $0 "\""}' | xargs shasum -a 256 | sort > checksumAndFilename.tmp && cat checksumAndFilename.tmp | awk '{print $1}' | uniq -D | uniq > checksum.tmp && grep -f checksum.tmp checksumAndFilename.tmp | tee duplicates.tmp && echo "output in \"duplicates.tmp\"" && rm checksumAndFilename.tmp checksum.tmp

The basic idea is to search the current directory and all subdirectories for images files, calculate a hash for each file, then sort the hashes and then list adjacent hashes, which would be duplicates. (If this is too much for your brain, just go to imymac and buy an app.)

Ok, let's go through the command in detail.

  1. Get all the image files in your directory and below. Update "*.jpg" to "*.png" or whatever you need.

    find . -type f \( -name "*.jpg" -o -name "*.gif" \)

  2. Surround the file name with double quotes, since some people still insist on the horrible, dasterdardly, awful practice of including spaces in names.

    awk '{print "\"" $0 "\""}'

  3. Pipe the names of the files into shasum to generate a hash

    xargs shasum -a 256

  4. Sort by the hash value so duplicates will be adjacent and write to a temp file

    sort > checksumAndFilename.tmp

    checksumAndFilename.tmp looks like this. The files with the same hash value would be duplicates.

    ff45b77226369d27b67772e72dfe8dc3387eff06  ./2010-07-04-2224-July4_036.jpg
    ff65e3611973092e61127439af6b3c82d0ee055a  ./2010-12-29-1408-IMG_9638.jpg
    ff680170b0451868a1bda027c801b78f55067366  ./2010-12-24-1010-IMG_9235.jpg
    ff918f6f8230deb3cd2208602dadb5c6f88039dc  ./2010-03-14-2025-IPhone_8146.jpg

    We are almost done, but how to only see hash values that are duplicates?

  5. Get only the hash values that are duplicates

    cat checksumAndFilename.tmp | awk '{print $1}' | uniq -D | uniq > checksum.tmp

  6. checksum.tmp looks like this. This are only the hash values that are duplicated.

  7. We have only the duplicated hash values. Let's match the hashes back with their filenames

    grep -f checksum.tmp checksumAndFilename.tmp

  8. We can see the first two are duplicates, and the next two are as well.

    0526e5586cc1e4d2d97e5cc813c8d9b698bc3df2  ./2010-11-28-0926-IMG_0300.jpg
    0526e5586cc1e4d2d97e5cc813c8d9b698bc3df2  ./IMG_0300.jpg
    075a137c8857c8b38555cf632d906ed0581b9224  ./2010-06-08-photoshoot012.jpg
    075a137c8857c8b38555cf632d906ed0581b9224  ./2010-06-08-photoshoot_012.jpg
  9. Write to the output file and the screen

    tee duplicates.tmp

  10. Let's remind ourselves where the output lives

    echo "output in \"duplicates.tmp\""

  11. Clean up our mess

    rm checksumAndFilename.tmp checksum.tmp

My gut tells me there's some ways to clean this script up. Please add a comment if you can improve the script.

Tuesday, March 15, 2022

How to Find IPhone's Unread Messages

 My IPhone has been declaring I have 1 unread message, but I can't find it.

The solution was actually easy.

 "Hey Siri, read me my unread messages." 

Siri read my one message and closed it.

Monday, March 14, 2022

Is Silver or the S&P 500 a Better Investment?

 Back in 1979 some friends of mine in Dallas were really into buying silver, as in pre-1965 silver quarters. They firmly believed the US financial system was on the verge of collapse due to congressional overspending. The US dollar would be worthless due to runaway inflation and the silver coins would be worth a fortune and be the de facto currency.

As a poor college student I didn't have much money to sock away in silver, but I bought 6 silver quarters which equals a little more than 1 troy oz of pure silver.

Was that a good investment?  Let's see. In 1979, silver was about $11. per oz.

This year, 2022, my ounce of silver is worth $24.

What if I'd invested that $24 in the S&P 500 in 1979? The index has risen 12% on average since 1979, so my stocks in 2022 would have a value of $3,120.

So, $24 or $3,120? You decide.

Sunday, March 06, 2022

What does Google know about me?

I just updated my advertising profile at Google. It's easy.

Visit and you'll see something like this:

You can click on subjects and remove them from your ad lineup. I removed "cats", but kept "dogs".

Wednesday, January 26, 2022

Free Online HTML Validator for an Entire Site -

I recently retired from 42 years of software development and have a little more time to work on my personal website,
I've been working on it for almost 30 years and some parts are a little, ... , crusty shall we say?

I found a wonderful online free website analyzer from the good folks at that will gently scan an entire website and show areas that need fixin'.