[mrtg] external command problems

Charles Sprickman spork at bway.net
Sun Apr 29 06:47:50 CEST 2007

On Thu, 26 Apr 2007, Steve Shipway wrote:

>> Sorry to be a nag, but does anyone have any ideas on this?  The script
>> output appears valid to me - right now it just spits out two numbers
> ie:
>> 0
>> 29
> Are you completely sure it is outputting
> 0\n29\n\n\n
> (obviously \n is a newline)?  Although lines 3&4 can be blank, they
> still need to exist.  This might be the cause of the problems.

The output was fine...  Apparently "0" always becomes "undef".

The reason my graphs weren't showing anything was that I had at some point 
in my tinkering removed the "gauge" option.  So mrtg was just sitting 
there waiting for the number to increment (which it really won't by more 
than a digit or two).

All is well now.  That "undef" thing was really throwing me as I was 
interpreting that as "your script fed me something I can't parse".

I tested with a simpler script that just spit out two digits, and that 
showed me what was going on.

Thanks all,


> Steve

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