[Nagiosplug-devel] [ nagiosplug-Patches-1025841 ] fixes for check_log

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Patches item #1025841, was opened at 2004-09-10 15:06
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Category: Bugfix
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Richard Luys (luys)
Assigned to: Nobody/Anonymous (nobody)
Summary: fixes for check_log

Initial Comment:
In my humble opinion (backed up by first-hand 
experience), the check_log script is not yet complete.

When the logfile to check becomes empty (for instance 
after logrotate or a reboot), the 'older copy of the logfile' 
still contains data. Since these files are compared with a 
diff-statement: diff $logfile $oldlog, all lines in the oldlog 
will be checked for a match with the given query-string, 
resulting in a lot of notifications.

The way I solved it, is as follows: 
instead of diff $logfile $oldlog, I use diff $logfile $oldlog | 
grep \^\< 

This results in diff outputting ONLY NEW lines in the 
logfile. If the logfile becomes empty, all diff-output lines 
start with '>' and will not be checked.

This is probably a quick-and-dirty solution, but works fine 
for us (so far)...

Another issue I found in this script:
lastentry=`$GREP "$query" $tempdiff | $TAIL -lines=1`

I am not sure which Os'es understand tail -lines=1 but 
afaik tail -1 is more common...



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