Systemd-tmpfiles

Systemd-tmpfiles is a component of the systemd suite that manages volatile and temporary files and directories by creating, cleaning, and deleting them based on configuration files found in /etc/tmpfiles.d, /run/tmpfiles.d, and /usr/lib/tmpfiles.d. It uses configuration files with a specific format to define actions for different paths, ensuring that temporary data does not accumulate and consume unnecessary storage space.

RHEL 7, 8, and other Red Hat Derivatives

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On Red Hat Enterprise Linux (RHEL) 7 and later, the cleanup of the /tmp directory is managed by systemd-tmpfiles. The configuration file responsible for defining the cleanup parameters for /tmp is located at:

/usr/lib/tmpfiles.d/tmp.conf

Within this file, the v directive specifies the path to be cleaned, along with permissions, ownership, and the retention period. For example, a common entry for /tmp would resemble:

v /tmp 1777 root root 10d

This line indicates that files and directories within /tmp older than 10 days are subject to deletion during the systemd-tmpfiles --clean operation, which is typically executed periodically by a systemd timer.

The configuration file: /usr/lib/tmpfiles.d/tmp.conf is called by systemd-tmpfiles-clean.service