On 7/9/11, Kenneth Porter shiva@sewingwitch.com wrote:

I have a Bash script, currently run a couple times an hour from cron, that pulls data from an old Windows DB by rsync, converts it to SQL, and injects it into a MySQL DB for display in a LAMP-based app. (Make and Perl are also involved to minimize the number of tables touched and to clean up the SQL generated by Pxlib.)

I'd like to add the ability to refresh the data immediately from the web app, but I don't want it to trample on the periodic script and corrupt the data.

Offhand, I think checking for a lock file before starting is probably the easiest way to do it. That's what I do for scripts that are cronjobs but can also be initiated manually. However, this might not work if your web app is inserting/updating the data in MySQL directly rather than simply starting a new import process as I'm assuming.