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Home > Archive > Unix Programming > August 2007 > multiple pipes and tail -f
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multiple pipes and tail -f
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| pvsnmp@yahoo.com 2007-08-22, 1:23 pm |
| Hi,
I have been trying to do the following but it doesn't seem to work.
tail -f <filename> | grep <some string> | grep <some other string>
where <filename> is the name of any file to which new lines are added,
something like a log file for example.
Is there some restriction on the number of pipes which could be used
while using tail -f ?
I would like use sed instead of the last grep in the example above,
but for simplicity I have used second grep.
Thanks and Regards,
Prashant
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| Ivan Gotovchits 2007-08-22, 1:23 pm |
| pvsnmp@yahoo.com wrote:
> Hi,
> I have been trying to do the following but it doesn't seem to work.
> tail -f <filename> | grep <some string> | grep <some other string>
>
> where <filename> is the name of any file to which new lines are added,
> something like a log file for example.
> Is there some restriction on the number of pipes which could be used
> while using tail -f ?
> I would like use sed instead of the last grep in the example above,
> but for simplicity I have used second grep.
>
> Thanks and Regards,
> Prashant
I think it is better to ask it in comp.unix.shell
P.S. As I know, there're no restrictions.
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| Pipe Dope 2007-08-22, 7:23 pm |
| pvsnmp@yahoo.com wrote:
>Hi,
>I have been trying to do the following but it doesn't seem to work.
>tail -f <filename> | grep <some string> | grep <some other string>
>
>where <filename> is the name of any file to which new lines are added,
>something like a log file for example.
>Is there some restriction on the number of pipes which could be used
>while using tail -f ?
>I would like use sed instead of the last grep in the example above,
>but for simplicity I have used second grep.
You might be running into buffering issues.
Try "grep --line-buffered"
More at: http://www.pixelbeat.org/programming/stdio_buffering/
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| pvsnmp@yahoo.com 2007-08-23, 1:21 am |
| On Aug 23, 2:51 am, hates...@hatespam.com (Pipe Dope) wrote:
> pvs...@yahoo.com wrote:
>
>
> You might be running into buffering issues.
>
> Try "grep --line-buffered"
>
> More at:http://www.pixelbeat.org/programming/stdio_buffering/
Hi,
Yes, --line-buffered seems to work.
Thanks,
Prashant
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