Delete oldest files/directories - but not all!

I have an automated process that deposits generated files in subdirs (that it creates) of a fixed directory.  So it looks like

/mydir/20031201/file
/mydir/20031203/file
etc.

What I want to do is setup a cron job that will clean up the mydir directory.  Here's how I want it to work:

I want to delete all the directories (the 20031203-type, not mydir), and their files, EXCEPT for the newest 10.  So if there's only 10 dirs or less when the cleanup script runs, it does nothing.  If there are 33 dirs, it deletes the 23 oldest.

I'm trying to do this with ls -c, and then pipe through head and/or tail, but I just can't see a way to do it that way.

How can I write a script that will do this?
kwdAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Karl Heinz KremerCommented:
The command "ls -t /mydir/*" lists all directories ordered by their creation time. The newest is first, and the oldest last. All you now have to do is strip off the first 10 names: The command "tail +11" does exactly this: It lists all lines starting with the 11th. If you now combine these commands, and call rm -rf on all lines, you are done:

ls -t /mydir/* | tail +11 | xargs /bin/rm -rf
You should however test this first with the echo command instead of /bin/rm:
ls -t /mydir/* | tail +11 | xargs echo


0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Karl Heinz KremerCommented:
BTW: I used -t (modification time) instead of -c (creation time) because I would want to keep a directory that was recently modified around for a little while
0
kwdAuthor Commented:
Brilliant, thanks.  I missed the "+" option in man tail, and I didn't know about xargs.  Your script works perfectly!
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Linux OS Dev

From novice to tech pro — start learning today.