systemd: Expand discussion of Automatic File Creation and Deletion

[bdubbs@…]

In the systemd version of the book, section 7.10.4. Configuring Automatic File Creation and Deletion, we need a little more detail, perhaps with an example.

In my case, I wanted to change the way files in /tmp are removed. To do this, I needed to create /etc/tempfiles.d; cp /usr/lib/tmpfiles.d/tmp.conf /etc/tempfiles.d; and edit that new tmp.conf file.

Note that the offending line in this case was

q /tmp 1777 root root 10d

Note that the config item q is not exactly intuitive. The man page says q is similar to v and v means "Create a subvolume ..." or something similar to d and mentions 'quota groups'. Buried in there is that statement " On non-btrfs file systems, this line type is identical to d"

[bdubbs@…]

Fixed at revision 11340.