Tag Archives: touch

CLI

Increment modified date of files in a directory based on first file

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I had an issue in Immich where it was sorting pictures by their modified date. The modified dates are random, but the filenames are not. I wanted the album to sort by filename, and to do that I needed to get each filename to have a modified time in the same order. This was my solution (run within the directory in question) :

date=$(date -r $(ls | head -1) +%s); for file in *.jpg; do touch -m -d "@$date" $file; ((date+=1)); done

This bash one-liner does the following:

  • Sets a date variable by taking the modified date of the first file in the directory and converting it to epoch time
  • Goes through each JPG file in the directory and executes a touch command to set the date of that file to the date variable
  • Increments the date variable by 1 before processing the next file

The end result is now the order the files are in by modified date match their filename order.

CLI

Manipulate EXIF data with jhead

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From time to time I find I need to edit the date taken metadata on pictures. I’ve discovered that jhead is a wonderful tool to accomplish this. It has many options, but the ones I use most frequently are the following:

  • –mkexif Create EXIF data for a picture that does not contain it
  • -ft Set picture’s filesystem modified date to match the EXIF date taken contained in the picture
  • –dsft Set the EXIF date taken date of the picture to match the modified time of the filesystem for that picture

You can use wildcards, which is super convenient. To create metadata for all JPG files in a current directory:

jhead -mkexif *.JPG

I like to use touch in conjunction with jhead to set exif picture taken times for files that don’t have any metadata but I know the date they were taken:

jhead -mkexif *.jpg
touch -t 201410201700 *.jpg
jhead -dsft *.jpg

For pictures which have correct metadata but incorrect modified date (downloaded pictures, for example) simply do the following:

jhead -ft *.jpg

Neat.

Update 7/15/2018

I came across this helpful article which outlines how to view exif information from the command line using the identify command. It requires that imagemagick be installed.

identify -verbose *.jpg | grep "exif:"

Update 12/9/2018

This is the syntax I use to set the time of the picture to a specific date:

jhead -tsYYYY:MM:DD-HH:mm:ss <filename>