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Test exit status misinterpreted in scripts when buit without job control
From: |
Dan Cross |
Subject: |
Test exit status misinterpreted in scripts when buit without job control |
Date: |
Thu, 04 Aug 2016 16:05:55 +0000 |
Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-unknown-linux-gnu'
-DCONF_VENDOR='unknown' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash'
-DSHELL -DHAVE_CONFIG_H -I. -I.. -I../include -I../lib -g -O2
uname output: Linux spitfire.my.domain 3.13.0-88-generic #135-Ubuntu SMP Wed
Jun 8 21:10:42 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-unknown-linux-gnu
Bash Version: 4.3
Patch Level: 30
Release Status: release
Description:
When bash is built without job control, shell scripts that use
the 'test' builtin (e.g., via '[') in conditionals may take the
wrong branch becuase the exit status of the test is lost.
Repeat-By:
Configure without job control. Via e.g.,
./configure --prefix=/usr --bindir=/bin --without-bash-malloc
--disable-nls --disable-job-control
Invoke the resulting shell and run the following sequence of commands:
$ cat > foo.sh
if [ $# -lt 2 ]
then
echo "$# args is less than 2"
else
echo "$# args is not less than 2"
fi
$ chmod +x ./foo.sh
$ ./foo.sh 1 2 3 4
4 args is less than 2
$
Observe the output: '4' is not actually less than '2' yet the
script incorrectly reports it as such.
Note: we originally discovered this when porting 'bash' to a
new research operating system that does not support job control.
However, we were able to reproduce on Linux.
- Test exit status misinterpreted in scripts when buit without job control,
Dan Cross <=