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Full Discussion: Providing variable contents to awk
Top Forums Shell Programming and Scripting Providing variable contents to awk Post 302605019 by Corona688 on Tuesday 6th of March 2012 12:49:32 PM
Old 03-06-2012
That is a useless use of cat, to avoid unwanted side-effects and splitting for things in backticks you would generally do

Code:
while read LINE
do
        echo "Read $LINE"
done < inputfile

...but in this case I'm not sure why you're using a while loop at all. awk is quite capable of reading more than one line by itself.

Anyway.

When you do "$g" by itself, it assumes that's a command. For instance:

Code:
$ G="cat"
$G file

file contents.
...
...

$

So you're not actually printing the line into awk here -- you're running it as a command, and piping its output into awk.

What you're trying to do is more like echo $G | awk ...

...but I think your program would be best rewritten as:

Code:
awk -F, '{ print $2 }' filename

This User Gave Thanks to Corona688 For This Post:
compguy74
 

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LEARN ABOUT CENTOS

lksh

LKSH(1) 						    BSD General Commands Manual 						   LKSH(1)

NAME

     lksh -- Legacy Korn shell built on mksh

SYNOPSIS

     lksh [-+abCefhiklmnprUuvXx] [-+o opt] [-c string | -s | file [args ...]]

DESCRIPTION

     lksh is a command interpreter intended exclusively for running legacy shell scripts.  It is built on mksh; refer to its manual page for
     details on the scripting language.  It is recommended to port scripts to mksh instead of relying on legacy or idiotic POSIX-mandated behav-
     iour, since the MirBSD Korn Shell scripting language is much more consistent.

LEGACY MODE

     lksh has the following differences from mksh:

     o	 lksh is not suitable for use as /bin/sh.

     o	 There is no explicit support for interactive use, nor any command line editing or history code.  Hence, lksh is not suitable as a user's
	 login shell, either; use mksh instead.

     o	 The KSH_VERSION string identifies lksh as ``LEGACY KSH'' instead of ``MIRBSD KSH''.

     o	 lksh only offers the traditional ten file descriptors to scripts.

     o	 lksh uses POSIX arithmetics, which has quite a few implications: The data type for arithmetics is the host ISO C long data type.  Signed
	 integer wraparound is Undefined Behaviour.  The sign of the result of a modulo operation with at least one negative operand is unspeci-
	 fied.	Shift operations on negative numbers are unspecified.  Division of the largest negative number by -1 is Undefined Behaviour.  The
	 compiler is permitted to delete all data and crash the system if Undefined Behaviour occurs.

     o	 The rotation arithmetic operators are not available.

     o	 The shift arithmetic operators take all bits of the second operand into account; if they exceed permitted precision, the result is
	 unspecified.

     o	 The GNU bash extension &> to redirect stdout and stderr in one go is not parsed.

     o	 The mksh command line option -T is not available.

     o	 Unless set -o posix is active, lksh always uses traditional mode for constructs like:

	       $ set -- $(getopt ab:c "$@")
	       $ echo $?

	 POSIX mandates this to show 0, but traditional mode passes through the errorlevel from the getopt(1) command.

     o	 lksh, unlike AT&T UNIX ksh, does not keep file descriptors > 2 private.

SEE ALSO

     mksh(1)

     https://www.mirbsd.org/mksh.htm

     https://www.mirbsd.org/ksh-chan.htm

CAVEATS

     lksh tries to make a cross between a legacy bourne/posix compatibl-ish shell and a legacy pdksh-alike but ``legacy'' is not exactly speci-
     fied.

     The set built-in command does not have all options one would expect from a full-blown mksh or pdksh.

     Talk to the MirOS development team using the mailing list at <miros-mksh@mirbsd.org> or the #!/bin/mksh (or #ksh) IRC channel at
     irc.freenode.net (Port 6697 SSL, 6667 unencrypted) if you need any further quirks or assistance, and consider migrating your legacy scripts
     to work with mksh instead of requiring lksh.

MirBSD								    May 2, 2013 							    MirBSD
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