Retroactively published on 8 Mar 2019. A while ago I started keeping a journal of TILs, and I’ve decided to share some of them.
Today I learned about the sticky bit.
I set up a Samba share on a Raspberry Pi for our household scanner. The scanner dumps files into a shared directory, and we can triage them from our computers or phones. It seemed to be working fine, but then I realized that I wasn’t able to delete files. I could create and read files, but delete just didn’t work.
Here’s how the directory looked:
$ ls -lah / | grep scanner
drwxrwxrwt 2 scanner scanner 4.0K Oct 7 18:52 scanner
At first I figured there was some sort of group permissions problem. But adding
my user to the scanner group didn’t solve it.
Turns out it was the t - the sticky
bit. This was preventing any user who
wasn’t scanner from deleting files in that directory.
Removing the sticky bit fixed the problem.
$ sudo chmod -t /scanner