Date: Thu, 14 Jul 2005 23:43:39 -0400 From: Hakim Singhji <hzs202@gmail.com> To: freebsd-questions@freebsd.org Cc: Dan Nelson <dnelson@allantgroup.com> Subject: Re: Problem Piping iostat -c to awk! Message-ID: <42D730EB.6070905@gmail.com> In-Reply-To: <20050715032319.GA98600@dan.emsphone.com> References: <42D7236A.6010803@gmail.com> <20050715032319.GA98600@dan.emsphone.com>
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Dan,
| iostat -c 300 1 | awk '!/[a-zA-Z]|^$/ {print $1}'
This doesn't seem to work for me... awk tells me:
awk syntax error at source line 1
***
/[a: Event not found.
Not sure how to allow awk to delete two top rows of iostat... other that
the grep option -v. Does not seem to be working in awk.
Dan Nelson wrote:
| In the last episode (Jul 14), Hakim Singhji said:
|
|>I am having problems with a shell script that I am writing. I am
|>looking to pipe the output of iostat to awk however the shell is
|>hanging... even at the command line it hangs. The code looks like
|>this:
|>
|> # iostat -c 300 2 | egrep -v '[a-zA-Z]|^$' | awk '{print $1}'
|>
|>This code hangs for me... now when I just pipe iostat through the
|>egreped patter it is fine. It's when it is passed to awk that I have
|>problems... now of course if I simplify the output to:
|>
|> # iostat | egrep -v '[a-zA-Z]|^$' | awk '{print $1}'
|>
|>it works just fine... so it has to be the awk. What is the problem?
|
|
| Actually grep is the culprit. It buffers its output when piped to
| another program for efficiency. Try adding --line-buffering, or just
| let awk handle your regular expression:
|
| iostat -c 300 1 | awk '!/[a-zA-Z]|^$/ {print $1}'
|
|
- --
Hakim Singhji
New York University
"But where danger is, grows the saving power also" (qtd. in Heidegger 28).
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