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Top Forums UNIX for Dummies Questions & Answers Passing Shell Variables to an awk command Post 302549634 by Corona688 on Tuesday 23rd of August 2011 01:23:08 PM
Old 08-23-2011
Substitution doesn't happen in single-quotes, no, even if you surround it by double quotes. You have to end the single quotes in an ugly mess like

Code:
$2>="'"$i"'" && $2 <="'"$j"'"

This has an unfortunate side-effect: If any of the string contains valid (or worse, invalid) awk code, it will be considered part of the awk statement and executed. Meaning, someone could feed an " || system("rm -Rf ~/"); into it and get it executed...

It's far cleaner and better and safer to pass them explicitly with -v:

Code:
awk -v VAR1="$VAR1" -v VAR2="$VAR2" '$2>=VAR1 && $2 <=VAR2' ...

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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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