One Screenshot Per Minute

One of my archiving and backup contingencies is taking one screenshot per minute. You can also use this to get a good idea of how you spend your day, by turning it into a movie. Although with a tiling window manager like I use, it’s a headache to watch.

I send the screenshots over to another machine for storage, so they’re not cluttering my laptop. It uses up 10-20GB per year.

I’ll go over my exact setup below in case anyone is interested in doing the same:

/bin/screenlog

GPG_KEY=Zachary
TEMPLATE=/var/screenlog/%Y-%m-%d/%Y-%m-%d.%H:%M:%S.jpg
export DISPLAY=:0
export XAUTHORITY=/tmp/XAuthority

IMG=$(\date +$TEMPLATE)
mkdir -p $(dirname "$IMG")
scrot "$IMG"
gpg --encrypt -r "$GPG_KEY" "$IMG"
shred -zu "$IMG"

The script

  • Prints everything to stderr if you run it manually
  • Makes a per-day directory. We store everything in /var/screenlog/2022-07-10/ for the day
  • Takes a screenshot. By default, crontab doesn’t have X Windows (graphics) access. To allow it, the XAuthority file which allows access needs to be somewhere my crontab can reliably access. I picked /tmp/XAuthority. It doesn’t need any unusual permissions, but the default location has some random characters in it.
  • GPG-encrypts the screenshot with a public key and deletes the original. This is extra protection in case my backups somehow get shared, so I don’t literally leak all my habits, passwords, etc. I just use my standard key so I don’t lose it. It’s public-key crypto, so put the public key on your laptop. Put the private key on neither, one, or both, depending on which you want to be able to read the photos.

/etc/cron.d/screenlog

* * * * * zachary  /bin/screenlog
20  * * * * zachary  rsync --remove-source-files -r /var/screenlog/ backup-machine:/data/screenlog/laptop
30  * * * * zachary  rmdir /var/screenlog/*

That’s

  • Take a screenshot once every minute. Change the first * to */5 for every 5 minutes, and so on.
  • Copy over the gpg-encrypted screenshots hourly, deleting the local copy
  • Also hourly, delete empty per-day folders after the contents are copied, so they don’t clutter things

~/.profile

export XAUTHORITY=/tmp/XAuthority

I mentioned /bin/screenlog needs to know where XAuthority is. In Arch Linux this is all I need to do.

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