bash and ksh: variable lost in loop in bash? Post: 302228796

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Top Forums Shell Programming and Scripting bash and ksh: variable lost in loop in bash? Post 302228796 by estienne on Monday 25th of August 2008 12:47:01 PM

08-25-2008

Registered User

bash and ksh: variable lost in loop in bash?

Hi,

I use AIX (ksh) and Linux (bash) servers. I'm trying to do scripts to will run in both ksh and bash, and most of the time it works. But this time I don't get it in bash (I'm more familar in ksh).

The goal of my script if to read a "config file" (like "ini" file), and make various report. I really simplified my script and reproduce the problem. It seems that variable inside "while loop" are lost in bash, but not in ksh?

Here's the script:

#!/bin/bash

function read_configfile
{
typeset configfile="$1"
typeset Hostname="$2"

grep '=' $configfile | sed "s/'//g" | while read ligne; do
variable="$(echo "$ligne" | awk -F= '{print $1}')"
value="$(echo "$ligne" awk -F= '{print $2}')"
eval "$variable='$value'"
done

echo "Affectation=$Affectation"
}

read_configfile bogus.in $(hostname)

And the bogus.in file:

Affectation=Yes life is good

When run, the output is

Affectation=

So... First of all I want to understand WHY the behavior is different. Is it because the way the "pipe" are processed?

Second, I found a way to bypass this. I just put every "variable=value" in a file (echo equation >>file), and outside the loop I'm doing an eval, and it works. But I would prefer NOT to use temporary file, so if you have any suggestions...

Thanks.

Last edited by estienne; 08-25-2008 at 01:55 PM..

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echo

echo(1B)					     SunOS/BSD Compatibility Package Commands						  echo(1B)

NAME

       echo - echo arguments to standard output

SYNOPSIS

       /usr/ucb/echo [-n] [argument]

DESCRIPTION

       echo writes its arguments, separated by BLANKs and terminated by a NEWLINE, to the standard output.

       echo  is useful for producing diagnostics in command files and for sending known data into a pipe, and for displaying the contents of envi-
       ronment variables.

       For example, you can use echo to determine how many subdirectories below the root directory (/) is your current directory, as follows:

	   o	  echo your current-working-directory's full pathname

	   o	  pipe the output through tr to translate the path's embedded slash-characters into space-characters

	   o	  pipe that output through wc -w for a count of the names in your path.

		    example% /usr/bin/echo "echo $PWD | tr '/' ' ' | wc -w"

       See tr(1) and wc(1) for their functionality.

       The shells csh(1), ksh(1), and sh(1), each have an echo built-in command, which, by default, will have precedence, and will be  invoked	if
       the  user  calls  echo without a full pathname. /usr/ucb/echo and csh's echo() have an -n option, but do not understand back-slashed escape
       characters. sh's echo(), ksh's echo(), and /usr/bin/echo, on the other hand, understand the  black-slashed  escape  characters,	and  ksh's
       echo() also understands a as the audible bell character; however, these commands do not have an -n option.

OPTIONS

       -n    Do not add the NEWLINE to the output.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWscpu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       csh(1), echo(1), ksh(1), sh(1), tr(1), wc(1), attributes(5)

NOTES

       The -n option is a transition aid for BSD applications, and may not be supported in future  releases.

SunOS 5.11							    3 Aug 1994								  echo(1B)

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