Date: Mon, 17 Dec 2012 08:57:16 -0800 From: Devin Teske <devin.teske@fisglobal.com> To: Polytropon <freebsd@edvax.de> Cc: Devin Teske <dteske@freebsd.org>, FreeBSD Questions <freebsd-questions@freebsd.org>, Jack Mc Lauren <jack.mclauren@yahoo.com> Subject: Re: using AWK Message-ID: <0EFF6378-A6EE-4222-8F3A-5F437E69D3BB@fisglobal.com> In-Reply-To: <20121217172316.79d8e198.freebsd@edvax.de> References: <1355744359.61103.YahooMailNeo@web160104.mail.bf1.yahoo.com> <18B0C79B-AF04-48D1-AF26-1B8A8B3641C1@fisglobal.com> <20121217172316.79d8e198.freebsd@edvax.de>
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On Dec 17, 2012, at 8:23 AM, Polytropon wrote:
> On Mon, 17 Dec 2012 08:16:26 -0800, Devin Teske wrote:
>>
>> On Dec 17, 2012, at 3:39 AM, Jack Mc Lauren wrote:
>>
>>> Hi guys
>>>
>>> How can I read a file which contains a number and assign that number to a variable via awk programming? By the way, I want to use this awk program in a shell script.
>>>
>>> Thanks in advance
>>
>> Try this:
>>
>> awk -v file=/etc/ttys 'BEGIN { getline line <file; printf "First line from %s: %s\n", file, line }'
>
> Or more verbose:
>
>
>
>
> #!/bin/sh
>
> filename=$1
>
> echo "file is ${filename} with content:"
> cat ${filename}
>
> echo "calling awk..."
> awk -v filename=$filename "BEGIN {
> getline no < filename
> close filename
> print no
> print no * 2
> }"
>
>
>
>
> # EXAMPLE:
> # --------
> #
> # % ./awkvar.sh /tmp/no.txt
> # file is /tmp/no.txt with content:
> # 12345
> # calling awk...
> # 12345
> # 24690
>
>
>
> The example shows how to use the variable inside awk. You
> could get rid of the getline function in case the file
> contains only the number you're interested in. If you need
> further processing of the file, you can do that inside
> awk (e. g. omitting comment lines, obtain data from a given
> line number of specific pattern).
>
>
>
>
> --
> Polytropon
> Magdeburg, Germany
> Happy FreeBSD user since 4.0
> Andra moi ennepe, Mousa, ...
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