Hi, Thats a pretty good idea. But I was thinking of an option like the one in Fcron. Fcron doesn't allow to start the process if it's already running (started by fcron). So I guess there should be a similar option in crontab too.
Regards, Kurian Thayil On Thu, Apr 23, 2009 at 1:59 PM, Dave Ewart <da...@ceu.ox.ac.uk> wrote: > On Thursday, 23.04.2009 at 13:42 +0530, Kurian Thayil wrote: > > > I have 3 cron jobs enabled and all are relating to RSYNC. Now, all of > these > > scripts are run once in every 7 minutes all day. The problem occurs when > the > > scripts doesn't finish to execute in 7 minutes. This will result in > starting > > execution of the same script again and this will malfunction the setup. > > > > Is there an option in CRON, which always check if CRON has started the > > process and is already running? Cron should execute the script only if > the > > the process isn't running already. Any hints on this? > > Don't make it cron's responsibility to check whether the script is > already running. Make it the *scripts's* responsibility. > > For example, the script should create a marker file (or similar) when it > runs, deleting the marker file upon completion. The *first* thing the > script should do is check for the existence of the marker file and, if > it exists, then another instance of the script is already running; you > can then terminate the script at that point. > > e.g. (partly bash, partly pseudo-code, completely untested) > > MARKER=/home/username/tmp/marker.txt > if [ -e $MARKER ]; then > echo Script already running > exit > touch $MARKER > [...] > [... real script here ...] > [...] > rm $MARKER > > Dave. > > -- > Dave Ewart > da...@ceu.ox.ac.uk > Computing Manager, Cancer Epidemiology Unit > University of Oxford / Cancer Research UK > PGP: CC70 1883 BD92 E665 B840 118B 6E94 2CFD 694D E370 > Get key from http://www.ceu.ox.ac.uk/~davee/davee-ceu-ox-ac-uk.asc > N 51.7516, W 1.2152 > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.9 (GNU/Linux) > > iD8DBQFJ8CbpbpQs/WlN43ARAkHRAJ9Jn+w/m3JpIPFn131OVVVkgmKYOACglczD > MqzsbR6QH9Es1WsoUAZhTCk= > =iHhR > -----END PGP SIGNATURE----- > >
