On 22Apr2016 15:04, Jon LaBadie <mut...@jgcomp.com> wrote:
On Fri, Apr 22, 2016 at 12:34:48AM -0700, David Champion wrote:
* On 21 Apr 2016, Jon LaBadie wrote:
> Unless it has changed recently, bash runs redirected read
> commands in a sub-process. Thus the variable fn would not
> get set in the main process.
I haven't run into this (that I recall) with regular input redirection.
It does happen with piped input redirection (to a read) because the
pipeline terminal isn't the current shell.
yes:
read fn </dev/tty
no:
cat /dev/tty | read fn
Thanks for the correction David.
My negative bash experience was with pipes as in:
date | read wday mon day time zone yr
which works fine in ksh and zsh. I badly assumed
the limitation was to any redirection.
Yah, the active thing is not the readirect, it is that a pipeline needs to put
at least all but one command as separate processes, and most shells will make
all the commands separate processes (including the final "read" from your
example).
I usually do this:
date \
| { read wday mon day time zone yr
... use $wday etc here - in the same shell as the "read" ...
}
Cheers,
Cameron Simpson <c...@zip.com.au>
