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buffers readlines and general popen2 confusion...

I'm interested in taking the output of a daemonized shell script that
greps for patterns which would act as an argument to a script. Is it
better to write this stuff to file and visit the file every few seconds
or can this be done a better way. I'm hoping for a more elegant
solution. So far I've seen some troubling info about buffer overflows
with popen2 but it looks like the low-hanging fruit. I'm not a unixpro
so I want to make sure anything I tackle is best practice. Suggestions
welcomed.

-Aris

May 21 '06 #1
3 1067
ar**********@on et.eu wrote:
I'm interested in taking the output of a daemonized shell script that
greps for patterns which would act as an argument to a script. Is it
better to write this stuff to file and visit the file every few seconds
or can this be done a better way. I'm hoping for a more elegant
solution. So far I've seen some troubling info about buffer overflows
with popen2 but it looks like the low-hanging fruit. I'm not a unixpro
so I want to make sure anything I tackle is best practice. Suggestions
welcomed.

-Aris

Sounds like you should take a look at logdog. It uses fifo files to
send the output of /var/log/messages and greps them for patterns.
As the daemon just looks at the fifo file for any input, it is quite
efficient.

I could be way off base about what you are trying to do, but it still
might we worth a look.

http://caspian.dotconf.net/menu/Soft...gDog/v1.0-old/

-Larry Bates
May 21 '06 #2
In article <11************ **********@j33g 2000cwa.googleg roups.com>,
ar**********@on et.eu <ar**********@o net.eu> wrote:
I'm interested in taking the output of a daemonized shell script that
greps for patterns which would act as an argument to a script. Is it
better to write this stuff to file and visit the file every few seconds
or can this be done a better way. I'm hoping for a more elegant
solution. So far I've seen some troubling info about buffer overflows
with popen2 but it looks like the low-hanging fruit. I'm not a unixpro
so I want to make sure anything I tackle is best practice. Suggestions
welcomed.


I'm puzzled - a daemonised program normally closes stdin/stdout/stderr
and disconnects from its controlling terminal, so where is its output
going?


--
Jim Segrave (je*@jes-2.demon.nl)

May 21 '06 #3
That's just it. I was hoping to have python listening for events and
responding continually according to the demaons stdout. That's why I
mention popen2.

May 21 '06 #4

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