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Full Discussion: awk If expression - Return string if not true
Top Forums UNIX for Dummies Questions & Answers awk If expression - Return string if not true Post 302952468 by bakunin on Wednesday 19th of August 2015 08:33:51 AM
Old 08-19-2015
I think your main impediment is you need to know how awk script work:

Every awk-script consists of three parts (although each part is optional): the first part is marked with BEGIN and is executed before the first line of the input is read. The second part is not marked with a name and is executed every time a line of input is read. The last part is named END and is executed after the last line of input is read.

For instance:

Code:
awk 'BEGIN  {
               printf( "Here we start.\n" );
            }
            {
               print;
            }
     END    {
               printf( "Here it ends.\n" );
            }' /path/to/input

This will print the input file unaltered (the single "print" command in the middle does that), surrounded by "Here we start" at the top (the effect of the BEGIN clause) and "Here it ends" at the bottom (the effect of the END clause).

Your original script printed "no duplicates" several times because the process - deciding upon printing it or not, then printing it eventually - was done for every line over and over. Dons script worked because he put that into the END-part and just manipulated a flag without printing anything in the main part.

You should be able with this to change his script into doing whatever you want it to do.

I hope this helps.

bakunin
 

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LEARN ABOUT DEBIAN

paps

PAPS(1) 						      General Commands Manual							   PAPS(1)

NAME

       paps - UTF-8 to PostScript converter using Pango

SYNOPSIS

       paps [options] files...

DESCRIPTION

       paps reads a UTF-8 encoded file and generates a PostScript language rendering of the file. The rendering is done by creating outline curves
       through the pango ft2 backend.

OPTIONS

       These programs follow the usual GNU command line syntax, with long options starting with  two  dashes  (`-').   A  summary  of  options	is
       included below.

       --landscape
	      Landscape output. Default is portrait.

       --columns=cl
	      Number of columns output. Default is 1.
	      Please notice this option isn't related to the terminal length as in a "80 culums terminal".

       --font=desc
	      Set the font description. Default is Monospace 12.

       --rtl  Do right to left (RTL) layout.

       --paper ps
	      Choose paper size. Known paper sizes are legal, letter and A4. Default is A4.

       Postscript points
	      Each postscript point equals to 1/72 of an inch. 36 points are 1/2 of an inch.

       --bottom-margin=bm
	      Set bottom margin. Default is 36 postscript points.

       --top-margin=tm
	      Set top margin. Default is 36 postscript points.

       --left-margin=lm
	      Set left margin. Default is 36 postscript points.

       --right-margin=rm
	      Set right margin. Default is 36 postscript points.

       --gutter-width=gw
	      Set gutter width. Default is 40 postscript points.

       --help Show summary of options.

       --header
	      Draw page header for each page.

       --markup
	      Interpret the text as pango markup.

       --lpi  Set the lines per inch. This determines the line spacing.

       --cpi  Set the characters per inch. This is an alternative method of specifying the font size.

       --stretch-chars
	      Indicates  that  characters  should be stretched in the y-direction to fill up their vertical space. This is similar to the texttops
	      behaviour.

AUTHOR

       paps was written by Dov Grobgeld <dov.grobgeld@gmail.com>.

       This manual page was written by Lior Kaplan <kaplan@debian.org>, for the Debian project (but may be used by others).

								  April  17, 2006							   PAPS(1)
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