[ale] Explain Shell Script Behavior?

[Wandered Inn]

Jeff Hubbs wrote:
> 
> Maybe someone can explain the why behind an observation I made last night
> while examining a Linux system that had run out of space on its root
> partition.
> 
> This system runs a simple bash script every ten minutes (via cron) that goes
> out to a Web site and pulls down files.  Based on what it gets, it does one
> of two things (by way of an if statement): 1) runs sendmail to spit out a
> message OR 2) does nothing and terminates.  The "normal" operation is "2)
> does nothing and terminates" and that is what happens almost every time.
> 
> I noticed two unusual things:
> 
> *       I ran ktop while the script was running and while I saw wget
> executing (that's what pulls down the files), I also saw sendmail executing
> even though the condition to cause it to run was never true.
> 
> *       wget has some text output that scrolls up the screen if I execute it
> manually.  The reason that / filled up was because the file
> /var/spool/mail/jhubbs ("jhubbs" is the name of the account that runs the
> script) had been collecting text output from the script (including the wget
> text output), appending from each iteration of the script.
> 
> Why are these things happening, and how can I stop the accumulation of
> script output in that file (maybe add "> /dev/null" to the line in crontab)?

Exactly.

I'd suggest you post the actual script as it appears that your test is
not functioning as you expect.

> 
>         - Jeff
> 
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Until later: Geoffrey		esoteric at denali.atlnet.com

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