Fixing a systemd service 203/EXEC failure (no such file or directory)

To simplify, make sure to add a hash bang to the top of your ExecStart script, i.e.

#!/bin/bash

python -u alwayson.py    

When this happened to me it was because my script had DOS line endings, which always messes up the shebang line at the top of the script. I changed it to Unix line endings and it worked.

I think I found the answer:

In the .service file, I needed to add /bin/bash before the path to the script.

For example, for backup.service:

ExecStart=/bin/bash /home/user/.scripts/backup.sh

As opposed to:

ExecStart=/home/user/.scripts/backup.sh

I'm not sure why. Perhaps fish. On the other hand, I have another script running for my email, and the service file seems to run fine without /bin/bash. It does use default.target instead multi-user.target, though.

Most of the tutorials I came across don't prepend /bin/bash, but I then saw this SO answer which had it, and figured it was worth a try.

The service file executes the script, and the timer is listed in systemctl --user list-timers, so hopefully this will work.

Update: I can confirm that everything is working now.