Shell Programming and Scripting

Hi... I want to know whether if there is any alternative for cron.

I had written a script which checks for all system/application processes every 15 min(placed in cron though). But looks funny - what if cron daemon isn't running!! and expecting that script to update the OUTPUT FILE that CRON DAEMON IS NOT RUNNING?????

No Cron Daemon,No execution of script , No alert/update.

Is there any alternative, unlike installing/going for applications like Patrol for UNIX???

If you want my script, i can post but i think its not required.

Cheers,
Sai

On our systems cron is a critical process that may never not run. If it happens, then there it has to be restarted asap if possible. So far it never happened that it stopped so at least on AIX it was always very reliable.

You write your own script in an endless loop that does something every 15 mins, comparing som date (time) information or with sleep etc.

I'd say cron is the way to go.

definately agree with that!

If cron is not running, you need to look at why, and/or restart it asap.
Why do you think it's not running?

You might want to read this link:
https://www.unix.com/unix-dummies-que...s-working.html

are you trying to run your own crontab, roots crontab, or another priveledged users cron?

Might be helpfull to post the crontab entry here.
"But looks funny - " what's this supposed to mean?

Many thanks for the both the replies...
I had enough of curiosity to post my silly doubt, that made me FUNNY to think what if there is no CRON... Haha

cron is very well-established in the UNIX world, you can pretty much expect to find it wherever you go. Its concept is robust, reliable, and secure. Most 'alternatives' you will find to the standard cron amount to different implementations of cron... Likely the same thing that'd happen if this "Patrol" thing wasn't able to load itself and schedule things for whatever reason. If cron wasn't running, that would likely point to problems larger than your script... I've only managed to confuse cron once in my life -- by putting the system clock three months into the future by accident when it was already running.

It may seem a little odd to type things into a table file instead of enter them into a program, but cron is every bit as present and accounted for; just perhaps a little less direct, and that separation is one thing that makes it so dependable. Just make sure your user belongs to the cron group. 'patrol', if that program is what I think it is, it bears little resemblance to cron. cron's job is to run programs at scheduled times. Nothing more, nothing less. Remote monitoring would be done with different things -- though lots probably need cron

Though there is another cron-like thing for UNIX that I know of -- the at daemon. Fallen into disuse these days but you should still be able to install it if you want it. It lets you use relative times, which is occasionally useful. You could do echo /sbin/reboot' | at + 15 minute to reboot the system in 15 minutes.

Wow!!!

Just trudging through explanation/experience and is really good. Looks fine and dandy to me now about cron.... But still thinking - time for me to read more. Thanks a ton for your time.