STMPCLEAN(8) BSD System Manager's Manual STMPCLEAN(8)NAMEstmpclean — remove old files from a world-writable directory
SYNOPSISstmpclean [-t<timespec>] [-v] dir1 [dir2 ...]
DESCRIPTION
The stmpclean utility removes old files (and old empty directories) from
the specified directory. It'll be typically used to clean directories
such as ``/tmp'' where old files tend to accumulate.
The stmpclean utility never removes files or directories owned by root.
It is a feature, not a bug. Great care is taken while descending into
the directory, and the operation is secure. Anything that's not a direc‐
tory, regular file, or symbolic link is also left alone (because programs
like screen(1) create sockets and FIFOs under /tmp and expect them to be
long-lived; we accomodate this practice). Unlike floating around Perl
scripts that do the same task stmpclean never forks and consumes limited
amount of memory (these Perl scripts easily turn into forking bombs when
someone creates a lot a directories under ``/tmp''). If your system is
attacked and the attacker creates an extremely deep file hierarchy,
stmpclean won't add to the problem by crashing your system trying to
remove it. But it won't help you in fighting the attack, either, because
it descends only to a limited depth (currently, 30 levels). If stmpclean
determines a race condition it'll log the situation (you can look for the
word ``RACE'' in log files) and exit with a failure.
So, stmpclean will clean temporary directories for you fine when there
are no attacks, and, when there is an attack, stmpclean won't make the
situation worse (in particular, it cannot be tricked into removing files
outside specified directories or consume unlimited amount of resources).
The following option is available:
-t<timespec>
The time specification that follows the -t flag specifies how old a
file or a directory has to be before it will be removed. It can be
a string like `1w' (one week) or `4d5h' (four days plus five hours)
or `2m3s' (two minutes plus three seconds). The default is `3d'
(three days).
-v Be verbose: list each file deleted.
The stmpclean utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
The stmpclean utility will typically be run nightly from cron(8) as
stmpclean /tmp /var/tmp
In FreeBSD stmpclean invokation should be placed into the file
/etc/periodic/daily/110.clean-tmps. In other versions of BSD it should
go into the /etc/daily script. In Linux, check if you have
/etc/periodic, and if not, you can just run it from cron; usually you'd
have to edit /etc/crontab.
SEE ALSOcron(8)BUGS
When stmpclean removes a file from a directory, modification time of the
directory changes and it looks new to stmpclean when it examines it later
(if the directory became empty). Thus, removing a deep hierarchy can
take some time. Notice that this only delays removal of some empty
directories.
BSD April 29, 2024 BSD
