systemd-tmpfiles

What it does

How to write it

systemd-tmpfiles [OPTION]... [CONFIG-FILE]...

Main parts

Line types (tmpfiles.d)

d PATH MODE USER GROUP AGE

Create a folder; with AGE, clean old files in it.

D PATH …

Like d, but empty the folder at every boot (--remove).

e PATH …

Clean an existing folder by age; do not create it.

v / q / Q PATH …

Create a folder or btrfs subvolume (with quota).

f PATH MODE USER GROUP - TEXT

Create a file if missing (with TEXT as content).

F PATH …

Create or empty a file.

w PATH - - - - TEXT

Write TEXT into an existing file (for example in /sys or /proc).

L PATH - - - - TARGET

Create a symbolic link.

C PATH - - - - SOURCE

Copy a file or folder if the target is missing.

x PATH

Do not clean this path (exception).

X PATH

Do not clean this path, but clean what is inside.

r / R PATH

Remove the path (R = with content) at --remove.

z / Z PATH MODE USER GROUP

Fix rights, owner and SELinux label (Z = recursive).

t / T PATH - - - - ATTR

Set extended attributes.

h / H PATH - - - - ATTR

Set file attributes (like chattr).

a / A PATH - - - - ACL

Set POSIX ACLs.

Age

10d, 12h, 30m, 1w

Age units: days, hours, minutes, weeks.

-

No cleaning.

Most used

Nothing matches this filter.

$ run as a normal user# run as root (or with sudo)

1. 1See all rules in use

   $systemd-tmpfiles --cat-config | less
   $systemd-tmpfiles --tldr | grep -E '^[dDqQ] /(var/)?tmp'
   q /tmp 1777 root root 10d
   q /var/tmp 1777 root root 30d

2. 2A folder for an app that must exist after every boot

   #echo 'd /run/myapp 0755 myapp myapp -' > /etc/tmpfiles.d/myapp.conf
   #systemd-tmpfiles --create /etc/tmpfiles.d/myapp.conf
   #ls -ld /run/myapp
   drwxr-xr-x. 2 myapp myapp 40 Oct 27 13:10 /run/myapp

   /run is empty after every reboot; the rule makes the folder again at boot.

3. 3Delete old files automatically

   #echo 'd /var/tmp/cache 0750 root root 7d' > /etc/tmpfiles.d/cache.conf
   #systemd-tmpfiles --clean /etc/tmpfiles.d/cache.conf

   Files in /var/tmp/cache older than 7 days are removed now and every day by the timer.

4. 4Keep /tmp files longer than 10 days

   #cp /usr/lib/tmpfiles.d/tmp.conf /etc/tmpfiles.d/tmp.conf
   #sed -i 's|^q /tmp 1777 root root 10d|q /tmp 1777 root root 30d|' /etc/tmpfiles.d/tmp.conf

   The file in /etc with the same name replaces the package file.

5. 5Protect one folder from cleaning

   #echo 'x /tmp/build-keep' > /etc/tmpfiles.d/keep.conf

6. 6Empty a folder at every boot

   #echo 'D /var/lib/myapp/sessions 0700 myapp myapp -' > /etc/tmpfiles.d/sessions.conf

7. 7Make a link at boot

   #echo 'L /run/myapp.sock - - - - /var/lib/myapp/app.sock' >> /etc/tmpfiles.d/myapp.conf

8. 8Fix rights and SELinux labels at boot (DevSecOps)

   #echo 'Z /srv/app 0750 app app -' > /etc/tmpfiles.d/app-perms.conf
   #systemd-tmpfiles --create /etc/tmpfiles.d/app-perms.conf

9. 9Check the daily cleaning timer

   $systemctl list-timers systemd-tmpfiles-clean.timer
   $systemctl status systemd-tmpfiles-clean.service

10. 10Write a kernel setting at boot

    #echo 'w /sys/kernel/mm/transparent_hugepage/enabled - - - - never' > /etc/tmpfiles.d/thp.conf

11. 11User rules without root

    $mkdir -p ~/.config/user-tmpfiles.d
    $echo 'd %h/.cache/build 0700 - - 3d' > ~/.config/user-tmpfiles.d/build.conf
    $systemd-tmpfiles --user --clean

Nothing matches this filter.

Files

/etc/tmpfiles.d/*.conf

Your rules (win over package rules with the same name).

/usr/lib/tmpfiles.d/*.conf

Package rules.

/run/tmpfiles.d/*.conf

Runtime rules.

~/.config/user-tmpfiles.d/

User rules.

Exit codes