Date: Mon, 17 Dec 2012 17:23:16 +0100 From: Polytropon <freebsd@edvax.de> To: Devin Teske <dteske@freebsd.org> Cc: FreeBSD Questions <freebsd-questions@freebsd.org>, Jack Mc Lauren <jack.mclauren@yahoo.com> Subject: Re: using AWK Message-ID: <20121217172316.79d8e198.freebsd@edvax.de> In-Reply-To: <18B0C79B-AF04-48D1-AF26-1B8A8B3641C1@fisglobal.com> References: <1355744359.61103.YahooMailNeo@web160104.mail.bf1.yahoo.com> <18B0C79B-AF04-48D1-AF26-1B8A8B3641C1@fisglobal.com>
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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 ${filename} echo "calling awk..." awk "BEGIN { getline no < \"${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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