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Full Discussion: Awk miscellaneous doubts
Top Forums Shell Programming and Scripting Awk miscellaneous doubts Post 302488963 by royalibrahim on Wednesday 19th of January 2011 02:47:32 AM
Old 01-19-2011
Awk miscellaneous doubts

Hi,

I am having the following doubts on awk. Please clarify for me.

a) What does it mean?
Code:
awk '$1=$1'

and how does it change if I append FS="" to the above code?



b) What if I use awk -vFS="\n" (i.e) setting (input) field separator to newline char, then what will be the value of $0, $1...? I guess "$0" denotes the whole record right?



c) To find the duplicate record in a file, I may use
Code:
awk 'a[$0]++ > 1 {exit 1}' file
awk '{if (found[$1] > 0) print $1 " is a dup"; ++found[$1]}' file

Both returns the same result though the validation check is different. The first one checks for "> 1" and second one checks for "> 0". This is confusing.

Last edited by royalibrahim; 01-19-2011 at 08:06 AM..
 

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GRUB-RENDER-LABEL(1)                                               User Commands                                              GRUB-RENDER-LABEL(1)

NAME
grub-render-label - generate a .disk_label for Apple Macs. SYNOPSIS
grub-render-label [OPTION...] [OPTIONS] DESCRIPTION
Render Apple .disk_label. -b, --bgcolor=COLOR use COLOR for background -c, --color=COLOR use COLOR for text -f, --font=FILE use FILE as font (PF2). -i, --input=FILE read text from FILE. -o, --output=FILE set output filename. Default is STDOUT -t, --text=STRING set the label to render -v, --verbose print verbose messages. -?, --help give this help list --usage give a short usage message -V, --version print program version Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options. REPORTING BUGS
Report bugs to <bug-grub@gnu.org>. SEE ALSO
The full documentation for grub-render-label is maintained as a Texinfo manual. If the info and grub-render-label programs are properly installed at your site, the command info grub-render-label should give you access to the complete manual. grub-render-label (GRUB) 2.02-2ubuntu8.3 July 2018 GRUB-RENDER-LABEL(1)
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