using AWK

[Devin Teske]

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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