[SOLVED] Clearing /tmp

2handband · 12-27-2010, 07:46 AM

I've been using cron to clear /tmp at boot time but thought I'd try another method. After doing a little research I added the following line:

Code:

( cd /tmp && rm -rf -- * .* 2>/dev/null )

to /etc/rc.d/rc.S immediately after:

Code:

# Done checking root filesystem

And /tmp is not clearing out at boot time. This method seems to work for others; can somebody give me a hint as to what I might be doing wrong?

markush · 12-27-2010, 08:06 AM

Are you sure that the root-filesystem is mounted directly after checking it?
As you know the filesystem is checked when it is still unmounted.

I think you'll have to insert your code after this:

Code:

 # Remount the root filesystem in read-write mode
  echo "Remounting root device with read-write enabled."
  /sbin/mount -w -v -n -o remount /

Markus

tronayne · 12-27-2010, 08:32 AM

You might want to consider moving your code to /etc/rc.d/rc.local -- it runs last, so everything is mounted, daemons are going and all that sort of thing (that's where I do the /tmp clean out).

catkin · 12-27-2010, 09:41 AM

Should be OK. Try removing 2>/dev/null so you can see any error messages.

niels.horn · 12-27-2010, 09:55 AM

My desktop stays on for months in a row, so I run a simple script from cron.daily, deleting from /tmp all files that have not been accessed for a week.

2handband · 12-27-2010, 09:57 AM

Put it in /etc/rc.d/rc.local and it worked. Thanks!

hootee · 12-27-2010, 10:13 AM

If you clear /tmp in rc.local you remove these things that you create in rc.S

Code:

# Create /tmp/{.ICE-unix,.X11-unix} if they are not present:
if [ ! -e /tmp/.ICE-unix ]; then
  mkdir -p /tmp/.ICE-unix
  chmod 1777 /tmp/.ICE-unix
fi
if [ ! -e /tmp/.X11-unix ]; then
  mkdir -p /tmp/.X11-unix
  chmod 1777 /tmp/.X11-unix
fi

spoovy · 12-27-2010, 01:57 PM

Quote:

Originally Posted by 2handband

I've been using cron to clear /tmp at boot time but thought I'd try another method. After doing a little research I added the following line:

Code:

( cd /tmp && rm -rf -- * .* 2>/dev/null )

to /etc/rc.d/rc.S immediately after:

Code:

# Done checking root filesystem

And /tmp is not clearing out at boot time. This method seems to work for others; can somebody give me a hint as to what I might be doing wrong?

Can I just ask what is the point of the "-- * .*" section? I've not seen that string before.

If I (with my limited bash knowledge) wanted to do that i'd just use "./*"

I assume yours is better but why, what does it do? Thanks

rg3 · 12-27-2010, 02:00 PM

The double dash indicates rm that the rest of the arguments are positional and not options, should you have a file named "-i", for example. The first asterisk expands to the list of files and directories excluding the ones that are hidden. That's, I think, the point of the third dot-asterisk argument. However, that dangerously expands to include ".." too, so I'm not sure if I'd use it.

spoovy · 12-27-2010, 02:06 PM

Quote:

Originally Posted by rg3

However, that dangerously expands to include ".." too, so I'm not sure if I'd use it.

Thanks. You concern above has been raised in another thread on this topic, but apparently rm is designed to not remove . or .. so it should be safe.

EDIT - following hootee's post above, would it be an idea to avoid rmoving hidden files? ie

Code:

( cd /tmp && rm -rf -- * 2>/dev/null )

tronayne · 12-27-2010, 02:24 PM

Oh, yeah, I should have noted that the way I do this (from /etc/rc.local is with the find utility:

Code:

find /tmp -mtime +1 -print -exec rm -r {} \;

The -print is not necessary (it prints the list of stuff it's going to blow away, the list winds up in a log);
the -mtime +1 only finds stuff older than 1 day (so you don't blow away anything created during start up).
/tmp doesn't get blown away because it was modified a few seconds ago by start up stuff.
You can bury this is a shell program if you want (keeping the "standard Slackware way" intact; i.e., the check for an existing, executable file named rc.blah (which are, those rc.blah file, after all else is said, just shell programs)).

Hope this helps some.

hootee · 12-27-2010, 02:49 PM

Quote:

Originally Posted by tronayne

[*]the -mtime +1 only finds stuff older than 1 day (so you don't blow away anything created during start up).

But those directories in rc.S will be created only when they are missing. And if they are not created now they will be possibly removed.

spoovy · 12-27-2010, 03:01 PM

I think because they have just been created they will have timestamps < 1 day therefore be left alone.

Also, not being pedantic but just found this re "find -mtime" - http://www.unix.com/unix-dummies-que...f-one-day.html

So it looks like "-mtime +0" would find stuff older than 1 day, not "-mtime +1".

tronayne · 12-27-2010, 03:07 PM

Quote:

Originally Posted by spoovy

I think because they have just been created they will have timestamps < 1 day therefore be left alone.

Also, not being pedantic but just found this re "find -mtime" - http://www.unix.com/unix-dummies-que...f-one-day.html

So it looks like "-mtime +0" would find stuff older than 1 day, not "-mtime +1".

Maybe in 2005 (not that I can remember, though)...

-mtime +1 returns anything more than 24 hours old.

If you want "today," just use -mtime -1.

spoovy · 12-27-2010, 03:38 PM

Yeah you're right. I'm not sure the man page makes sense in that respect.

Shouldn't it be -atime rather than -mtime though? As the hidden files won't be modified by rc.local therefore won't be spared when your code cleans /tmp. But they will presumably be "accessed" by the rc.local script when it checks if they are present or not.

Or am I misunderstanding ?