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Full Discussion: Problem with pipes on infinite streams
Top Forums Shell Programming and Scripting Problem with pipes on infinite streams Post 302407987 by tokland on Saturday 27th of March 2010 01:12:01 PM
Old 03-27-2010
Hi!

Quote:
Originally Posted by alister
If using GNU grep:
Code:
counter | grep -m1 '[27]'

If that's not available:
Code:
counter | sed -n '/[27]/{p;q;}'

Thanks, those are good solutions. However, the grep in my code was just an example, let's imagine you cannot change how the stream is generated:

stream_generator | head -n1

By the way, using process substitution "works":

head -n1 <(stream_generator)

but it keeps the generator running on the background until the next match.
 

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LEARN ABOUT CENTOS

sas_disk_blink

SAS_DISK_BLINK(8)						      SDPARM							 SAS_DISK_BLINK(8)

NAME

       sas_disk_blink - blink the LED on a SAS disk

SYNOPSIS

       sas_disk_blink [--help] [--set NUM] [--verbose] DEVICE

DESCRIPTION

       This  bash shell script attempts to blink the LED on the SAS disk referred to by DEVICE. By default the LED will blink for 30 seconds. This
       is meant to help identify which disk corresponds to a given DEVICE.

       The script use the sdparm utility and manipulates the "Ready LED Meaning" (RLM) field in the Protocol specific port mode page in  order	to
       blink the LED.

OPTIONS

       Arguments to long options are mandatory for short options as well.

       -h, --help
	      print out the usage message then exit.

       -s, --set NUM
	      when  NUM is 0 then the RLM field is cleared. When NUM is 1 then the RLM field is set. When NUM > 1 then the SAS disk LED is made to
	      blink for NUM seconds. If this option is not given then the SAS disk LED is made to blink for 30 seconds.

       -v, --verbose
	      increase level or verbosity.

EXIT STATUS

       The exit status of this script is 0 when it is successful. Otherwise the exit status is that of the last sdparm	utility  called.  See  the
       sdparm(8) man page.

AUTHORS

       Written by D. Gilbert

COPYRIGHT

       Copyright (C) 2013 Douglas Gilbert
       This  software  is distributed under a FreeBSD license. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR-
       POSE.

SEE ALSO

       sdparm (sdparm)

sdparm-1.08							     May 2013							 SAS_DISK_BLINK(8)
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