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Full Discussion: Help in understanding awk expression
Top Forums Shell Programming and Scripting Help in understanding awk expression Post 302601317 by Corona688 on Thursday 23rd of February 2012 10:44:55 AM
Old 02-23-2012
Code:
# Before the program is run, set the variable n to the value "POINT"
-v n="POINT"

# For every line containing % somewhere:
'/%/ {
        # Print the entire line, followed by a newline, followed by "POINT"
        print $0 "\n" n
        # Skip this line so the '1' below doesn't print it
        next
# The '1' after the code block tells it to print every single line.
# It could be an expression too.
} 1' < file name

But I would've just written it as:

Code:
awk -v n="POINT" '/%/ { $0=$0"\n" n } 1'

To avoid the 'print' and the 'next'. For any line matching %, it just changes the current line( $0 ) to add "\nPOINT" to the end, so the print-every-line statement prints correctly in both cases.
This User Gave Thanks to Corona688 For This Post:
arun_maffy
 

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LEARN ABOUT DEBIAN

dpkg-awk

DPKG-AWK(1)						      General Commands Manual						       DPKG-AWK(1)

NAME

       dpkg-awk - Utility to read a dpkg style db file

SYNOPSIS

       dpkg-awk [(-f|--file) filename] [(-d|--debug) ##] [(-s|--sort) list] [(-rs|--rec_sep) ??] '<fieldname>:<regex>' ... -- <out_fieldname> ..

DESCRIPTION

       dpkg-awk  Parses  a  dpkg status file (or other similarly formatted file) and outputs the resulting records.  It can use regex on the field
       values to limit the returned records, it can also be told which fields to output, and it can sort the matched fields.

OPTIONS

       -f filename
       --file filename
	      The file to parse.  The default is /var/lib/dpkg/status.

       -d [#]
       --debug [#]
	      Each time this is specified, it increased the debug level.

       -s field(s)
       --sort field(s)
	      A space or comma separated list of fields to sort on.

       -n field(s)
       --numeric field(s)
	      A space or comma separated list of fields that should be interpreted as numeric in value.

       -rs ??
       --rec_sep ??
	      Output this string at the end of each output paragraph.

       -h
       --help Display some help.

       fieldname
	      The fields from the file, that are matched with the regex given.	The fieldnames are case insensitive.

       out_fieldname
	      The fields from the file, that are output for each record.  If the first field listed begins with ^, then the list  of  fields  that
	      follows will NOT be output.

BUGS

       Be  warned  that  the author has only a shallow understanding of the dpkg packaging system, so there are probably tons of bugs in this pro-
       gram.

       This program comes with no warranties.  If running this program causes fire and brimstone to rain down upon the earth, you will be on  your
       own.

       This program accesses the dpkg database directly in places, querying for data that cannot be gotten via dpkg.

AUTHOR

       Adam Heath <doogie@debian.org>

DEBIAN
								 Debian Utilities						       DPKG-AWK(1)
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