Re: Q: bash parameter expansion

[Chet Ramey]

Dmitry V. Levin wrote:
> On Mon, Apr 21, 2008 at 10:06:10AM +0200, Andreas Schwab wrote:
> > Dmitry V. Levin writes:
> >
> > > I wonder whether such difference in parameter expansion is valid:
> > >
> > > $ env -i sh -c 'fun() { echo "[${*#foo }]"; }; fun foo bar'
> > > [foo bar]
> > > $ env -i sh -c 'fun() { echo "[${*#foo}]"; }; fun foo bar'
> > > [ bar]
> > Works as documented:
> >
> > `${PARAMETER#WORD}'
> > `${PARAMETER##WORD}'
> >      The WORD is expanded to produce a pattern just as in filename
> >      expansion (*note Filename Expansion::).  If the pattern matches
> >      the beginning of the expanded value of PARAMETER, then the result
> >      of the expansion is the expanded value of PARAMETER with the
> >      shortest matching pattern (the `#' case) or the longest matching
> >      pattern (the `##' case) deleted.  If PARAMETER is `@' or `*', the
> >                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^
> >      pattern removal operation is applied to each positional parameter
> >                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >      in turn, and the expansion is the resultant list.
>
> Ouch, one more documented incompatibility between bash and dash.

Posix leaves it unspecified.  Bash and ksh do it one way; ash/dash and
zsh another.

Chet
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Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/