Questions tagged [process-groups]
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40 questions
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why cant pgid (process group leader)cant change its pgid?
Why is it that a Process Group Leader can't change its PGID? I know it sounds dumb for a leader to just abandon its own group, but what is the actual architectural reason behind this? What would ...
1
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1
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Prevent SIGINT propagation from subshell to parent shell in Zsh
I need to prevent SIGINT (Ctrl-C) from propagating from a subshell to its parent shell functions in Zsh.
Here's a minimal example:
function sox-record {
local output="${1:-$(mktemp).wav}"...
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Why does this script get to linger after having seemingly exited from Ctrl-C? [duplicate]
I have a script, script-A, which runs script-B. When run under the terminal, it terminates as expected from Ctrl-C, but when run via ssh it continues to silently run after Ctrl-C even though ssh ...
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3
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Send signal to process in tmux pane
Suppose that app X is running in the foreground in tmux pane. I'd like to send a given signal, e.g. SIGUSR1, to app X. Can I configure a tmux keybinding to send a signal to the currently-selected pane'...
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PID of background function "$!" gives wrong value
I am trying to capture the PID of a function executed in the background, but I seem to get the wrong number.
See the following script:
$ cat test1.sh
#!/bin/bash
set -x
child() {
echo "...
- 3,855
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Does a process’s parent have any significance from the perspective of its child?
In POSIX, processes are “related” to each other through two basic hierarchies:
The hierarchy of parent and child processes.
The hierarchy of sessions and process groups.
User processes have a great ...
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3
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how can I start a bash script in its own process group
I would like to start a bash script from another bash script, but start it in its own process group just like when you run it from the terminal.
There are a few similar questions, but I can't find an ...
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Process Group Leader's PID reused
Is it possible that a past Progress Group Leader's PID gets reused by an other process and this latter process starts a new Process Group?
In this case the first created process group and the second ...
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0
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Why are processes grouped by a PGID? [duplicate]
I am interested why processes are grouped additionally while having already a PPID and PID. What's the advantage of process groups?
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Why do we need to send SIGHUP to a newly orphaned process group containing a stopped process?
The Advanced Programming in the UNIX Environment book ("APUE") says
Consider a process that forks a child and then terminates. Although this is nothing
abnormal (it happens all the time), ...
- 107k
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Does kernel sending SIGHUP to a process group that becomes orphaned and contains a stopped process terminate all the processes by default?
In The Linux Programming Interface
To see why orphaned process groups are important, we need to view
things from the perspective of shell job control. Consider the
following scenario based on ...
- 107k
7
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Is there a way to change the process group of a running process?
Is there a way to change PID, PPID, SID of a running process? It would make sense for the answer to be no, but I'd like to make sure.
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Use waitpid for child having groupid 1
I searched a lot but didn't find a solution. So it can be silly question.
The format of waitpid is
pid_t waitpid (pid_t pid, int *status, int options)
The pid parameter specifies exactly which ...
- 6,072
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Why can't a process change the process group ID of one of its children after that child has called one of the exec functions?
From Advanced Programming in the Unix Environment:
A process can set the process group ID of only itself or any of its children.
Furthermore, it can’t change the process group ID of one ...
- 107k
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`sudo setsid command` does not spawn new process group?
I am looking at a scenario where I want to run a program / command with sudo as part of a software test. The commands are launched from a Python script based on the subprocess module. I am attempting ...
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