Re: -s flag

[Matthew Farwell <dylan@ibmpcug.co.uk>]

In article <9206300655.AA09921@redvax.mimosa.com> you write:
>| From: John (_You_ hide, they seek.) Mackin <john@vetsci.su.oz.au>
>|  Hey, can anyone on the list tell us
>| all if they have any reason at all for wanting -s?  Inquiring minds
>| want to know.
>|
>| ... I will always be willing to entertain rc features
>| that keep it compatible (in appropriate ways) with traditional shells.
>
>| From: Bob Gibson <rjg@sco.com>
>|
>| My editor, jove, starts up subshells with the -s option, and obviously
>| fails to do so if the shell doesn't support it.  In this case, the
>| correct thing to do would be to fix jove to make this configurable.
>
>I am the person who made JOVE invoke subshells with the -s flag.  I
>did it in about 1984, so I have forgotten some of the subtle
>details.  I will try to reconstruct them.
>
>First, a hint from SunOS 4.0.3 sh(1):
>
>     -s             If the -s option is present or  if  no  argu-
>                    ments remain commands are read from the stan-
>                    dard input.  Any remaining arguments  specify
>                    the   positional  parameters.   Shell  output
>                    (except for Special Commands) is  written  to
>                    file descriptor 2.
>
>Actually, the story goes back to about about 1976, when I was
>hacking on ed(1).  I changed the ! command so that the shell command
>was invoked in such a way that the current file could be referred to
>as $1.  This was extremely convenient.
>	!cp -p $1 $1.BAK
>	!chmod u+w $1
>	!pr $1 | lpr
>	!diff $1.BAK $1
>
>When I started hacking on JOVE, I naturally wanted this feature
>too.  The only way that I could get it to work with csh and and all
>versions of sh was to throw in the -s.  [I don't remember which
>failed without the -s]
>
>I want to keep using this feature.  I don't want to hack JOVE to
>allow the suppression of the -s for rc.  I think it is better to
>hack rc to accept -s like other UNIX shells.

It's a lot better to fix Jove than to 'fix' rc.  You could do this like
vi/ex does it.  If I execute a subshell command in vi, then any % is
replaced by the current filename, ie

:!mv % %.bak

would be expanded to 

:!mv foo foo.bak

etc.  This is a lot better than hacking a kludge into rc for the sake of
one editor.

Dylan.

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