jhead is a super useful command-line utility for manipulating images from digital cameras. It can do all sorts of nifty things such as rotating images that are marked as rotated in the EXIF header, deleting thumbnails embedded in the EXIF, etc… but what I just used it for was to correct a whole bunch of datetime stamps that were incorrectly set because I had the clock on my camera set wrong.

I only noticed when I got to picture 34 of our Italy and Spain trip that I had not adjusted the camera’s clock ahead by nine hours for the California to Italy time change. In a Cygwin bash prompt on my PC, I fixed this with:

$ jhead -ta+9:00 IMG_00[0-2]?.JPG IMG_003[0-3].JPG

After doing that, I noticed that the dates were ahead by a day for some reason. Perhaps I screwed up when I set the camera clock to adjust for the time change. No matter…

$ jhead -ta-24:00:00 IMG_003[4-9].JPG IMG_00[4-9]*.jpg IMG_0[1-5]*.JPG

And of course I forgot to change the clock back when we came back to California (IMG_0135.JPG) 🙂 :

$ jhead -ta-9:00 IMG_013[5-9].JPG IMG_01[4-9]*.JPG IMG_0[2-9]*.JPG