[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: RFE? |> ?
From: |
Chet Ramey |
Subject: |
Re: RFE? |> ? |
Date: |
Mon, 17 Dec 2007 22:55:21 -0500 |
User-agent: |
Thunderbird 2.0.0.9 (Macintosh/20071031) |
Linda Walsh wrote:
> I was wondering about a possible RFE and whether or not
> it is "inadvisable" or not. I'd be surprised if no one had
> thought of it -- so maybe there is a problem in doing it.
>
> Just like:
> &>word #(preferred syntax)
> and
> >&word
> are semantically equivalent to ">word 2>&1"
>
> Has it been thought to make
> |>word #(preferred form)
> semantically equivalent to "2>&1 | word" ?
There have been a few proposals for some mechanism combining redirection
and piping in this way, but I haven't really liked any of the suggested
notations. Note that "|>word" already has a well-defined meaning, and
your proposal isn't backwards-compatible. (That's a common problem.
The shell syntax is running out of reasonable character combinations.)
zsh uses |&, which is not bad, though ksh uses that to run a coproc. I
also like the vaguely rc-like [n]| to mean "n>&1 |", but that's a harder
parse.
> I note that ">|" is used to "emphatically overwrite a
> pre-existing file when the "-c" option is used to prevent
> overwrites. Why wasn't ">!" used for that?
Because >| was existing practice.
> Also, along the same lines (but less useful, IMO) would be
> &>>word #(append stderr & stdout to word)
That's reasonable.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
Live Strong. No day but today.
Chet Ramey, ITS, CWRU chet@case.edu http://cnswww.cns.cwru.edu/~chet/