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Re: Perhaps variables are re-initialized after a while loop


From: Chet Ramey
Subject: Re: Perhaps variables are re-initialized after a while loop
Date: Wed, 27 Dec 2000 11:54:54 -0500

> Machine Type: i386-suse-linux
> 
> Bash Version: 2.03
> Patch Level: 0
> Release Status: release
> 
> Description:
>       In the example below I have initialized a variable LINENUMBER
>         with the value zero. Then I enter a loop to process a number
>         of lines. In the loop the variable LINENUMBER is output.
>         After the end of the loop the variable is reset to the initial
>         value.

I don't see how you can expect any result other than what you got, since
you ran the while loop in a subshell.  A subshell cannot affect its
parent's environment.

Read the Bash FAQ, question E4.

>       The script (named x) I use to demonstrate the problem :
> 
> #!/bin/bash
>  let LINENUMBER=0
>  egrep -v  "^#|^ *$"  $1                                        |     \
>  (while read  LINE  REST
>  do
>      let LINENUMBER=$LINENUMBER+1
>      echo "$LINENUMBER   $LINE   $REST"
>  done )
>  echo "Total numbers of line : $LINENUMBER"
>  exit 0

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
( ``Discere est Dolere'' -- chet)

Chet Ramey, CWRU    address@hidden    http://cnswww.cns.cwru.edu/~chet/



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