[coreutils] coreutils-7.0 expr exposes long-standing bug in matlab startup script

[Nelson H. F. Beebe]

I've just filed a bug report with The Mathworks, vendor of the
widely-used Matlab matrix algebra system.  Their bin/matlab startup
script (all versions up to current) contains code like this:

        if [ `expr "$lscmd" : '.*->.*'` -ne 0 ]; then

With native versions of expr, and expr from GNU coreutils prior to
version 7.0, the expansion of lscmd usually begins "-rw-r--r--", but
the leading hyphen does not cause the word to be treated as an option.
For example:

        % expr "-rw-r--r--" : '.*->.*'
        0

However, in coreutils expr version 7.0, that hyphen raises an error:

        % expr "-rw-r--r--" : '.*->.*'
        expr: syntax error

        % expr " -rw-r--r--" : '.*->.*'
        0

This is NOT a coreutils bug, but since Matlab is widely deployed,
other sites will certainly hit this same bug in the coming days and
weeks, so this is just a heads-up to the coreutils developers.

Here is a typical patch:

% rcsdiff -r1.1 /usr/local/sys/matlab/matlab7.6/bin/matlab
===================================================================
RCS file: /usr/local/sys/matlab/matlab7.6/bin/RCS/matlab,v
retrieving revision 1.1
diff -r1.1 /usr/local/sys/matlab/matlab7.6/bin/matlab
178c178
< # $Revision: 1.1 $  $Date: 2008/10/13 20:40:34 $
---
> # $Revision: 1.2 $  $Date: 2008/10/13 20:48:49 $
211c211
< # $Revision: 1.1 $  $Date: 2008/10/13 20:40:34 $
---
> # $Revision: 1.2 $  $Date: 2008/10/13 20:48:49 $
401c401
<       if [ ! "$lscmd" ]; then
---
>       if [ ! " $lscmd" ]; then
422,423c422,423
<       if [ `expr "$lscmd" : '.*->.*'` -ne 0 ]; then
<           filename=`echo "$lscmd" | awk '{ print $NF }'`
---
>       if [ `expr " $lscmd" : '.*->.*'` -ne 0 ]; then
>           filename=`echo " $lscmd" | awk '{ print $NF }'`
467c467
<     RCSHEADER='$Revision: 1.1 $  $Date: 2008/10/13 20:40:34 $'
---
>     RCSHEADER='$Revision: 1.2 $  $Date: 2008/10/13 20:48:49 $'

-------------------------------------------------------------------------------
- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
- Department of Mathematics, 110 LCB    Internet e-mail: address@hidden  -
- 155 S 1400 E RM 233                       address@hidden  address@hidden -
- Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe/ -
-------------------------------------------------------------------------------