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Full Discussion: Two curious questions
Top Forums Shell Programming and Scripting Two curious questions Post 302709647 by Corona688 on Wednesday 3rd of October 2012 11:56:55 AM
Old 10-03-2012
a) There is a limit to how much stuff you can cram in a single shell variable. On some systems, this can be as small as a screenful or so, so don't go overboard.

b) If you're doing awk | awk | sed | cut | kitchen | sink, you probably could have done that all in one awk and saved yourself a lot of bother and CPU time. You don't need to use awk twice here:

Code:
awk '{ sum += $2 } END { print sum }' inputfile

c) That's also a useless use of cat, since awk does not need cat's help to read a file. You can use it as shown above, listing the filename on the end.

To answer question 2, there's actually a few ways to set more than one variable at once. read is a particularly flexible way of doing so. It helps if you know how many are coming, though, or can convince certain ones to come first. Everything you didn't list will get crammed into the last variable you list.

Code:
read SUM NUMBERS <<EOF
`awk '{ sum += $2; A[++L]=$0 } END { print sum ; for(N=1; N<=L; N++) print A[N]}' inputfile`
EOF

I saved all the numbers in the awk array A so I could print them later. This lets me print the sum first, and then the rest, letting me pick the sum out from the front with read.

You could also do
Code:
set -- `awk '{ sum += $2; A[++L]=$0 } END { print sum ; for(N=1; N<=L; N++) print A[N]}' inputfile`

SUM=$1
shift
REST="$*"

This User Gave Thanks to Corona688 For This Post:
jamie_123
 

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LEARN ABOUT DEBIAN

igawk

IGAWK(1)							 Utility Commands							  IGAWK(1)

NAME

       igawk - gawk with include files

SYNOPSIS

       igawk [ all gawk options ] -f program-file [ -- ] file ...
       igawk [ all gawk options ] [ -- ] program-text file ...

DESCRIPTION

       Igawk is a simple shell script that adds the ability to have ``include files'' to gawk(1).

       AWK programs for igawk are the same as for gawk, except that, in addition, you may have lines like

	      @include getopt.awk

       in your program to include the file getopt.awk from either the current directory or one of the other directories in the search path.

OPTIONS

       See gawk(1) for a full description of the AWK language and the options that gawk supports.

EXAMPLES

       cat << EOF > test.awk
       @include getopt.awk

       BEGIN {
	    while (getopt(ARGC, ARGV, "am:q") != -1)
		 ...
       }
       EOF

       igawk -f test.awk

SEE ALSO

       gawk(1)

       Effective AWK Programming, Edition 1.0, published by the Free Software Foundation, 1995.

AUTHOR

       Arnold Robbins (arnold@skeeve.com).

Free Software Foundation					    Nov 3 1999								  IGAWK(1)
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