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bug in string pattern matching
From: |
skt |
Subject: |
bug in string pattern matching |
Date: |
Tue, 18 May 2004 20:11:40 -0700 |
Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: linux-gnu
Compiler: i386-redhat-linux-gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='i386'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i386-redhat-linux-gnu'
-DCONF_VENDOR='redhat' -DSHELL -DHAVE_CONFIG_H -I. -I. -I./include -I./lib
-D_GNU_SOURCE -O2 -march=i386 -mcpu=i686 -g
uname output: Linux skywalker.ca.boeing.com 2.4.20-8 #1 Thu Mar 13 17:54:28 EST
2003 i686 i686 i386 GNU/Linux
Machine Type: i386-redhat-linux-gnu
Bash Version: 2.05b
Patch Level: 0
Release Status: release
Description:
[Detailed description of the problem, suggestion, or complaint.]
There is a bug in how string pattern matching works.
Repeat-By:
[Describe the sequence of events that causes the problem
to occur.]
Run this script:
#!/bin/sh
# 5/18/04 - S.K.Tazuma
#
# Code below demonstrates a bug in bash
# when run on RedHat Linux 8.0/9.0
# which uses bash version 2.05b(0).
# Also happens with 2.05a and 2.05.
#
# It does not happen on 2.03 or 2.04.21 versions of bash.
# Nor does it happen on 2.05b.0(8) cygwin version of bash (running
# on Windows of course). Since the version is the same as the one
# that shows the bug on Linux, this might imply a library problem.
# But since it doesn't occur when running the 2.04.21 version of bash
# on RedHat 9.0, that would suggest the problem is in the bash
# source code.
echo "BASH_VERSION = $BASH_VERSION"
echo ''
list='aaa bbb zzz AAA BBB ZZZ'
for str in $list
do
if [[ $str == [A-Z]* ]]
then
echo yes on str = $str
else
echo no on str = $str
fi
done
echo ''
for str in $list
do
case $str in
[A-Z]*)
echo yes on str = $str
;;
*)
echo no on str = $str
;;
esac
done
echo ''
echo 'the correct result for the above'
echo 'should be a "no" on each lower-case string,'
echo 'and a "yes" on each upper-case string'
echo ''
echo 'the correct result for the below'
echo 'should be a "yes" on each lower-case string,'
echo 'and a "no" on each upper-case string'
echo ''
for str in $list
do
if [[ $str == [a-z]* ]]
then
echo yes on str = $str
else
echo no on str = $str
fi
done
echo ''
for str in $list
do
if [[ $str == [ab-z]* ]]
then
echo yes on str = $str
else
echo no on str = $str
fi
done
echo ''
echo 'for a bash with the bug,'
echo 'note how the behavior changed in the last group,'
echo 'just because 'b' was listed in the glob [] pattern'
---------the output of the above script on RedHat 8.0 and 9.0 is:
BASH_VERSION = 2.05b.0(1)-release
no on str = aaa
yes on str = bbb
yes on str = zzz
yes on str = AAA
yes on str = BBB
yes on str = ZZZ
no on str = aaa
yes on str = bbb
yes on str = zzz
yes on str = AAA
yes on str = BBB
yes on str = ZZZ
the correct result for the above
should be a "no" on each lower-case string,
and a "yes" on each upper-case string
the correct result for the below
should be a "yes" on each lower-case string,
and a "no" on each upper-case string
yes on str = aaa
yes on str = bbb
yes on str = zzz
yes on str = AAA
yes on str = BBB
no on str = ZZZ
yes on str = aaa
yes on str = bbb
yes on str = zzz
no on str = AAA
yes on str = BBB
no on str = ZZZ
for a bash with the bug,
note how the behavior changed in the last group,
just because b was listed in the glob [] pattern
Fix:
[Description of how to fix the problem. If you don't know a
fix for the problem, don't include this section.]
- bug in string pattern matching,
skt <=