bug in bash v2.05b

[Philippe Berthault]

Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i686' -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu' -DCONF_VENDOR='pc' -DSHELL -DHAVE_CONFIG_H  -I.  -I. -I./include -I./lib -D_GNU_SOURCE  -O2 -march=i386 -mcpu=i686
uname output: Linux frcls2015 2.4.18-14 #1 Wed Sep 4 13:35:50 EDT 2002 i686 i686 i386 GNU/Linux
Machine Type: i686-pc-linux-gnu

 

Bash Version: 2.05b
Patch Level: 0
Release Status: release

 

Description:
========

  The command like in "liste | while read variable" doesn't work correctly.

 

Repeat-By:
=======

   See script example below.

 

Script example:

===========

flag=INITIAL
echo "initial flag = $flag  Pid= $$"
echo

 

echo "1
      2
      3" | while read var
do
   echo "old flag = $flag  Pid= $$"
   flag="MODIFIED($var)"
   echo "new flag = $flag  Pid= $$"
done
echo
echo "final flag = $flag  Pid= $$"

Problem:

======

The script returns:

 

initial flag = INITIAL  Pid= 6547

 

old flag = INITIAL  Pid= 6547
new flag = MODIFIED(1)  Pid= 6547
old flag = MODIFIED(1)  Pid= 6547
new flag = MODIFIED(2)  Pid= 6547
old flag = MODIFIED(2)  Pid= 6547
new flag = MODIFIED(3)  Pid= 6547

 

final flag = INITIAL  Pid= 6547

 

As you can see, the final flag is false.

The same script using ksh on a AIX system gives the correct result,

so bash and ksh are not compatibles.

 

Fix:
==

 To fix the problem, I uses the "for var in" instead of " | while".