On 11/03/2011 14:23, McKown, John wrote:
There's a discussion going on over on the MVS-OE forum (which I
started) about the /tmp subdirectory. It's gone away from my original
towards how to keep it clean. So I thought I'd ask the UNIX wizards
over here what the "industry standard" is.
I don't speak for "industry", but here are some Linux standards:
http://www.pathname.com/fhs/pub/fhs-2.3.html#TMPTEMPORARYFILES
http://www.pathname.com/fhs/pub/fhs-2.3.html#VARTMPTEMPORARYFILESPRESERVEDBETWEE
One thing mentioned by a
person boiled down to "delete all the files in /tmp which belong to a
specific user when the last process which is running with that UID
terminates" (rephrased by me). This got me to thinking. Is there any
need for a file in /tmp to exist when there is no process running by
a given user?
On a strict reading of the above, you can't rely on a /tmp file existing
"between invocations of the program", in other words when a file isn't
actively held open by a process. This would break many many shell
scripts I've read and written over the years :)
The typical way to clear up /tmp is with the tmpwatch utility, fired
from cron, which selects files to delete based on their last access
timestamp. Some distros go further and clean out /tmp completely on
every boot.
find /tmp -type f -exec ls -ln {} \; |\ awk '{print $3;}'|\ sort
-u|\ while read XUID; do echo Processing UID: $XUID; ps -u $XUID -U
$XUID>/dev/null || find /tmp -type f -uid $XUID -exec rm; done
I can see this approach yielding a lot of false negatives; i.e. leaving
files in place because UID has some unrelated process running.
If you're desperate to have a tidy /tmp, a frequent call to tmpwatch
along these lines might work:
tmpwatch --atime -all --fuser 6 /tmp
This 6-hour deadline is a lot more severe that Redhat's default of 10 days.
Before doing that, however, I'd question why the /tmp directory is so
space-constrained. If software isn't cleaning up its own stuff, fix it!
One further trick is to unlink a /tmp file while it's open, which
guarantees cleanup as soon as the process ends.
Cheers,
Phil
----------------------------------------------------------------------
For LINUX-390 subscribe / signoff / archive access instructions,
send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit
http://www.marist.edu/htbin/wlvindex?LINUX-390
----------------------------------------------------------------------
For more information on Linux on System z, visit
http://wiki.linuxvm.org/
