Named pipe does not wait until completion in bash

问题:

In the following test.jl creates an output.txt and generates some console output. console output is very well handled. but control returns immediately after echo even before output.txt is created completely. placing a wait in between echo and mv causes an indefinite wait. Should a carriage return be passed to the pipe without killing the pipe yet?

mkfifo pipe
sleep 1000000 > pipe &
julia <pipe >stdout.txt 2>stderr.txt &

echo "include(\"test.jl\")" > pipe
mv output.txt temp/
echo "include(\"test2.jl\")" > pipe

Thanks!

回答1:

I understand that test.jl and test2.jl both write to output.txt so you have to move the file to another directory before running test2.jl or test2.jl expects output.txt in temp/ directory and you have to move it there before text2.jl runs.

If yes then the following code should solve the problem:

mkfifo pipe
sleep 1000000 > pipe &
julia <pipe >stdout.txt 2>stderr.txt &

echo "include(\"test.jl\")" > pipe
echo "mv(\"output.txt\", \"temp/\")" > pipe
echo "include(\"test2.jl\")" > pipe

In this way Julia runs mv command and you make sure that it is executed after test.jl but before test2.jl.

But actually we are getting to a point where it would be better to write a Julia script named e.g. script.jl:

include("test.jl")
mv("output.txt", "temp/")
include("test2.jl")

and run it using julia script.jl.