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Parameter expansion problem involving ${*#*--}

From: chak
Subject: Parameter expansion problem involving ${*#*--}
Date: Tue, 3 Oct 2000 11:15:48 +1100

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i386-redhat-linux-gnu' 
-D_FILE_OFFSET_BITS=64  -I.  -I. -I./include -I./lib -I/usr/include -O2 
-march=i386 -mcpu=i686
uname output: Linux enki 2.2.16-22 #1 Tue Aug 22 16:49:06 EDT 2000 i686 unknown
Machine Type: i386-redhat-linux-gnu

Bash Version: 2.04
Patch Level: 11
Release Status: release

        Parameter expansion including pattern matching misbehaves in an
        admittedly obscure case.  More precisely, the expansion of


        returns the wrong value for certain values of $* containing more than
        one occurrence of the substring `--'.  The problem seems to be
        confined to the special variable $* and does not occur with "normal"
        (alphanumeric) variables.

        The problem can be reproduced using the following shell script:


          echo 'Value of ${*}:      ' ${*}
          echo 'Value of ${*#*--}:  ' ${*#*--}
          echo 'Assigning $* to $bla'
          echo 'Value of ${bla}:    ' ${bla}
          echo 'Value of ${bla#*--}:' ${bla#*--}

        Assuming that the script is stored in an executable file called
        `bash-bug', upon execution of

          % bash-bug -- --delete

        the output is

          Value of ${*}:       -- --delete
          Value of ${*#*--}:   delete
          Assigning $* to $bla
          Value of ${bla}:     -- --delete
          Value of ${bla#*--}: --delete

        Note the difference in the expansion of ${*#*--} and ${bla#*--}.

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