Re: Not so useless use of cat

[Dennis Williamson]

On Tue, Sep 16, 2014 at 2:03 AM, Ralf Goertz <address@hidden> wrote:

> Am Sat, 13 Sep 2014 12:53:48 -0600
> schrieb Bob Proulx <address@hidden>:
>
>
> > Dennis Williamson wrote:
> > > Bob Proulx wrote:
> > > >   { for i in file[12] ; do cat "$i" ; done ;} > both
>
> > > There's no need for the curly braces and the last semicolon.
> >
> > Of course you are totally right.  I was distracted by the subshell as
> > a concept.  For re-stitching file with redirections a subshell isn't
> > needed and a list is convenient.
> >
> > > Note that the loop in this case can be replaced by
> > >
> > > cat file[12] > both
> > >
> > > I failed to spot that in my earlier reply.
> >
> > Me too.  (But usually these are from more complex examples that can't
> > be simplified as much.  It is just that all of the details aren't
> > shown.)
>
> Actually things are more complicated. I do need the /dev/stdout part. I
> obiously don't have the problem with `cat' but with some other program
> that doesn't write to stdout per se and expects a -o parameter for the
> output file. And this program just accepts one input file. I merely used
> the first `cat' in my example to make my point. So what I wanted was
>
> $ for i in file[12] ; do program -i "$i" -o /dev/stdout ; done > outfile
>
> which I assumed to be elegant and would do as I expected except it
> didn't and I really thought it could have been a bug. That's why I
> reported it here.
>
> Thanks for all replys,
>
> Ralf
>
>
>
Does your program support using a hyphen to represent stdout (some do)?

    program -i "$i" -o -

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