Questions tagged [coprocesses]

Question 1

Suppose I have some process that when ready will output to stdout. Even though I want my script to run asynchronously with respect to that process, I still want the script to block and wait on that ...

Question 2

I am playing with the coproc of Bash and I am failing to understand something. I started with the following example: Example#1 $ coproc MY_BASH { bash; } [1] 95244 $ echo 'ls -l; echo EOD' >&&...

Question 3

outer.sh: ls -l /proc/$$/exe coproc cat ./inner.sh kill $! inner.sh: ls -l /proc/$$/exe set | grep COPROC || echo No match found coproc cat kill $! When I run ./outer.sh, this gets printed: ...

Question 4

I don't understand this sentence about Coprocesses in the bash man page: Since the coprocess is created as an asynchronous command, the coproc command always returns success. The return status of a ...

Question 5

Start some command with zpty: zpty -d x ; zpty x 'echo hi' ; sleep 1 How do I read its output now that it has exited? zpty -r x Returns 2, and this behavior seems expected per the manpage.

Question 6

I have a requirement to make a function in a zsh shell script, that is called by command substitution, communicate state with subsequent calls to the same command substitution. Something like C's ...

Question 7

I currently try to start background process with coproc and update a name reference variable. My not working code: function updateVariable(){ local -n myVar="${1}" #i=0; while : do ...

Question 8

I'm trying to feed to file descriptor .mp3 files the with the dummy interface of vlc, i.e., cvlc, in order to add to a playlist on the fly or override the entire file descriptor with new data (new ....

Question 9

I'm trying to do a simple shell script that will make my raspberry's bluetooth discoverable but i'm facing some issues. My raspberry is running Raspbian. Running this through command line works ...

Question 10

The intent of the test script1 below is to start an "outer" coprocess (running seq 3), read from this coprocess in a while-loop, and for each line read, print a line identifying the current iteration ...

Question 11

I am trying to create a function that can run an arbitrary command, interact with the child process (specifics omitted), and then wait for it to exit. If successful, typing run <command> will ...

Question 12

Note this passage from man bash ( emphasis mine ): Coprocesses A coprocess is a shell command preceded by the coproc reserved word. A coprocess is executed asynchronously in a subshell, as if ...

Question 13

I have read that $coproc < command > is different from $< command > & in that coproc will execute command in a sub-shell process. But when I tested it, it worked just like $< ...

Question 14

I'm trying to get the following code to read from a main input then read that in one function then be able to send that into the input of another function but i am having trouble getting it to work ...

Question 15

While having a go at Convert date in bash shell, I tried GNU awk's coprocess feature: gawk -F, -v cmd='date +"%Y-%m-%d %H:%M:%S" -f-' '{print $5 |& cmd; cmd |& getline d; $5 = d}1' foo This ...

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Questions tagged [coprocesses]

coproc redirect to stdout

Bash coproc with python

How does bash know about its parent's coprocess in this situation, and why does a shebang line change it?

Return value vs return status of a coprocess

zsh, zpty: How to read the output of a process after it has exited?

coproc and named pipe behaviour under command substitution

Using coprocess to write a name referenced variable in BASH

Usage of cvlc with coproc

Coproc in bash script

Is it possible to have multiple concurrent coprocesses?

Run command in background with foreground terminal access

How does bash coprocess achieve its pipelining?

Is coproc <command> the same as <command> &? [duplicate]

inter process comunication in bash read commands in multiple background functions

Why does this gawk coprocess hang?

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