I have a process that's writing a lot of data to stdout, which I'm redirecting to a log file. I'd like to limit the size of the file by occasionally copying the current file to a new name and truncating it.
My usual techniques of truncating a file, like
cp /dev/null file
don't work, presumably because the process is using it.
Is there some way I can truncate the file? Or delete it and somehow associate the process' stdout with a new file?
FWIW, it's a third party product that I can't modify to change its logging model.
EDIT redirecting over the file seems to have the same issue as the copy above - the file returns to its previous size next time it's written to:
ls -l sample.log ; echo > sample.log ; ls -l sample.log ; sleep 10 ; ls -l sample.log
-rw-rw-r-- 1 user group 1291999 Jun 11 2009 sample.log
-rw-rw-r-- 1 user group 1 Jun 11 2009 sample.log
-rw-rw-r-- 1 user group 1292311 Jun 11 2009 sample.log
Take a look at the utility split(1), part of GNU Coreutils.