Package: mksh
Version: 39.3.20101101-1
Severity: wishlist
Tags: upstream
Hi Thorsten,
Recently I found myself debugging a pipeline with "tee".
Unfortunately the logs grew large very quickly, so as a stopgap
measure I used a compressor.
mkfifo backflow
... <backflow |
tee >(xz -1 >log-one.xz) |
... |
tee >(xz -1 >log-two.xz) |
... |
tee >(xz -1 >log-three.xz) >backflow
This construct is also handy when one wants to update the current
environment downstream from some other process.
while read -r line
do
... something interesting with line ...
accum=$(updated result)
done < <(upstream process)
: print result
printf "%s\n" "$accum"
The semantics:
<( ... ) - runs ... in a subshell in the background, with its
output connected to a pipe. The "<( ... )"
expression evaluates to a filename that can be
opened to read from that pipe.
>( ... ) - runs ... in a subshell in the background, with its
input connected to a pipe. The ">( ... )"
evaluates to a filename that can be opened to write
to that pipe.
On Linux and similar OSes this is typically implemented using
/proc/fd. A more portable implementation would use FIFOs.
What do you think? Is it worth implementing in mksh?
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