A process is an instance of a computer program that is being executed.

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wait and recycling of PID

I have a concern whereby in a script, I will be calling parallel versions of a function to run in the background and then issuing a wait. a () { sleep $1 } a 10 & PIDs="$PIDs $!" a 50000 & ...
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642 views

Finding Process Info Associated to a Given Port in HP-UX

I need to find information for a process that's using a given port number, such as 8080. More specifically, I'm interested in finding out the full path of the program. How can I do that in HP-UX?
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340 views

Command for killing specific PID provided by previous command

Sometimes I need to kill a process (the reasons why are not important). And I know I can find that process with the following command: lsof -i :8080, being my candidate the last process in the output ...
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1answer
286 views

Run a command in background that sets env var or define function

> export foo=1 & [1] 9016 [1] + done export foo=1 > echo $foo > I know when running a command with & you spawn a new process and the export foo=1 is not setting env vars in ...
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1answer
100 views

Solaris 10 system - used disc space keeps on increasing even after deleting the directory

I deleted a directory on slice mmf but it came back - the size is still same and also it keeps increasing. The reason for deleting the directory is that I couldn't find the process linked to creating ...
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2k views

fork() and how signals are delivered to processes

I program that I wrote in C fork()'s off a child process. Neither process will terminate. If I launch the program from the command line and press control-c which process(es) will receive the interrupt ...
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2k views

Sorting the output of `ps`

I am trying to understand why ps does not behave the way I expect it to. From the man pages, the following command should display ppid and lstart, with items sorted by lstart order. However when I run ...
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1k views

How to use pgrep inside bash script correctly?

I'm running a GUI program called zeal(compiled from src) and add a script(zeal.sh) for the executable: #!/bin/bash if pgrep zeal &>/dev/null; then printf "already on\n" else ~/tools/...
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4k views

Why is the PGID of my child processes not the PID of the parent?

So I keep reading everywhere that this command should terminate all child processes of the parent process: kill -- -$$ Using a negative ID with the kill command references a PGID and from the ...
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192 views

How to find out the reason a command/code was executed on Linux?

I have a complex embedded Linux software running on a gentoo derivative, on which a certain piece of code gets executed regularly every ~84 minutes. Sweeping through the main code to find places where ...
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1answer
614 views

How does the piping in this command ultimately achieve to kill the process?

I have seen the following line in a bash script for killing a process(in this case started with the command loadgen): ps xww | grep -i "loadgen" | grep "PATTERNMATCH_FACT.xml" | cut -c1-5 | xargs -i ...
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Bind9 — How to find which programs are making which dns lookups?

Using bind9 on a laptop shows lots of nonsense domains when network connectivity is down: Oct 18 19:56:18 lap3 named[1536]: error (network unreachable) resolving './NS/IN': 128.63.2.53#53 Oct 18 19:...
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126 views

How can I recover suspended processes after restarting X?

I had several instances of Firefox running, which I suspended. I think I used 'the GUI' (KDE's System Activity), which I think is the same as kill -19. Normally this works fine - I can resume the ...
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2answers
183 views

Absolute path to currently-running zsh?

Sometimes the output of ps -p $$ shows the absolute path to the currently-running zsh, % ps -p $$ PID TTY TIME CMD 1027 ttys005 0:00.11 /usr/local/bin/zsh but not always: % ps -p $$...
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748 views

When vfork is called is parent process really suspended?

As much as I know when vfork is called child process uses the same address space as that of the parent and any changes made by the child process in parents variables are reflected onto parents process....
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653 views

Current environmental variables of a process

This question relates to this answer. Is it possible to get the current (not initial) environmental variables of a process by making a child process and checking its initial environmental variables? ...
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4answers
865 views

How to get the id of a very short child process if the parent is known?

I'm looking for a way to get the PID of a short child process in Linux. The process is instant from a human perspective. I know the parent process which will spawn the child process. Is there a way ...
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3answers
747 views

Print process ID (PID) of a Matlab instance

To run my Matlab scripts, I've created a shell script to which I give two parameters - the path to the matlab file ($1) and to the log file ($2): nohup time matlab -some_parameters -r "run $1;exit" &...
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What process is sending TCP SYNs on Solaris 10?

Some process on my Solaris 10 machine is sending TCP SYNs to a remote machine. The remote machine never responds, so the connection is not established. How do I find out what process is initiating ...
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574 views

Prevent users from killing processes that they own

I have started some processes (window based) from user's .bashrc file. I want to prevent users from killing those processes. Is there a way to transfer the process to superuser so that a normal user ...
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2answers
1k views

wait does not wait

If i have a file called myprogram containing sleep 200 date Run this in the background: $ sh myprogram & i want to know when myprogram has completed by using wait command $ cat >notify ...
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507 views

Redirecting/grep'ing an existing shell's STDOUT

I run a lot of long running processes (simulations) that print progress to STDOUT. I occasionally forget to redirect to STDOUT to a file I can grep, and it's usually too far along to restart. ...
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8k views

How do you make a cross-process locking in Linux (C/C++)?

I need to make sure one process executes only in one instance at a time. On Windows you could use named mutex. But I have no idea what to use on Linux. I think I've seen an approach were app creates ...
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506 views

Need for thread_info structure in Linux 2.6 Kernel

Prior to the Linux 2.6 kernel, struct task_struct was present at the end of the kernel stack of each process. There was no thread_info struct concept. But in Linux 2.6 kernel, instead of task_struct ...
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20 views

Changing the current working directory of a certain process

Can I change the current working directory of a certain process? For example, I am running a process that has the pid 1000. Right now, its current working directory is ~. I want to change its current ...
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83 views

What are the default stdin and stdout of a child process?

I would like to know what are the default stdin and stdout of a child process (if there are such defaults). Are stdin and stdout of a child process the same as its parent process? Is this something ...
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When interrupting a process, does a memory leak occur?

Lets say I created a program in c/c++, where I manually allocated some variables. Then while running the program, I send an interrupt signal (Ctrl-C). Are those variables freed from memory, or will ...
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80 views

How can I kill process by specific name and exclude root processes

Not a long time ago we found out about pkill and we had in mind to start using it in a setuid (for root) script for global clean-up of processes. This could save us lots of stupid maintenance where ...
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119 views

How to sort ps output to find processes realtime priority and identify processess currently occupied running queue

How to properly identify real-time processes currently occupied CPU queue and count them using ps? I know there is a bunch of fileds like prio,rtprio,pri,nice but do not know correct to use. It seems ...
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179 views

Long-running R script is getting killed automatically

I'm attempting to run an experiment for my masters thesis that involves an R script that has to run for quite a while (up to 24 hours of 100% cpu usage). It's a single-core process, and as far as I ...
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42 views

How to find what processes run by the user right now?

Once again, I'm a beginner and I can't find the right command. I want to view the processes that I'm currently running.
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646 views

How can I know thread names that run on specific core

I am working in Java code. My code makes specific Java threads run on specific cores. In this code, I give names to Java threads. I need a Linux command that enables me to know the threads' names that ...
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3k views

Where is PCB on linux

A PCB is a process control block , this is its definition on Wikipedia Process Control Block (PCB, also called Task Controlling Block,[1] Task Struct, or Switchframe) is a data structure in ...
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98 views

Result from kernel returned to what process?

When a process requires actions that require kernel mode, it uses a system call. So, how are the results returned to the process?
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2k views

Difference between process in background and daemon [duplicate]

What is technically the difference of a process that started in foreground and was manually put into background and a daemon? Do they have different properties?
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How do I know if acct is running? (The Unix system accounting)

I have installed the acct package and it is running because I can see file activity in the log file. I know there is the command accton on to turn it on, but how do I determine that its running short ...
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Capture complete process structure/stack

There are a lot of java processes running on the server, generally, we capture the PIDs of the java processes using command 'ps -ef | grep java'. In general, the java processes have a lot of jars in ...
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Which script from /etc/init.d/ started the process?

Let's say we have a PID of a process and we know that it was started by init during startup. How do we find the script name that started it? One way is to run grep $PROCESS_NAME /etc/init.d/*, but ...
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How can I kill the top CPU/IO process quickly?

I find that sometimes my Linux will stop responding, so I need to switch to another terminal with CtrlAltF2, and type a command to kill the top CPU usage process or top IO usage process, so that the ...
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1k views

Solution to get data from memory of a process

If I'm using Firefox and filling out a big form (with lots of text to write), and for some reason I accidentally press F5 and all my text in the forms is lost, I can use e.g. HxD on Windows to ...
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411 views

Monitoring process activities using system calls only (without utilities like `top`)

I want to obtain information about memory used by different users and different processes which users are running and statistics about those processes like memory consumption, execution speed, etc., ...
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2k views

A tee >( process ) is truncating its stdout when writing a file

When I use tee to pipe stdout directly to a "specific block of code" (which then writes the modified data to a file), I always get the full complement of exptected output lines in the file. ...
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1answer
992 views

Start X as a user other than root

I know some distro's (Moblin? ) have X starting as a user other than root already... What is required to do this? What steps need to be taken? I don't think it matters but I think X is started by KDM ...
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1answer
20 views

Start new process group in .xinitrc

I have a statusbar (lemonbar) to which I pipe the output of a couple of scripts (time, battery, volume, etc.). These scripts, and the statusbar itself, are all started in a single bash script ...
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1answer
103 views

sigint not being propagated to background child process

I need to send SIGINT to terminate a process gracefully but I can't. This is a sample, because the environment in which the execution occurs is 'unknown' (a bash script in travis.com) I managed to ...
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1answer
53 views

Get all files open for writing with pid, recursively

Given a pid, I can get all the files open for writing something like: lsof -p 28827 | awk '$4 ~ "[wW]"{print $(NF-1), $NF}' One of those ends up being a pipe: 28827 232611 pipe I want to look-up ...
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How to get the PID of a sub process across to the parent process in a bash shell script?

My shell script is as following: #!/bin/bash ./process1 #It will create a sub process: sub_process1 while [ condition ]; do break done kill -9 process1 and sub_process1 In my script, it will ...
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138 views

What could be happening between pidof and kill to cause “no such process”?

I've inherited quite a bit of code and am looking at a cron job that restarts a service once an hour, no other scripts touch this process and this code is ran. #The name of the process has been ...
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1k views

Limit maximum number of concurrent scp processes running on a host

I am facing a problem where I have a fleet of servers which contain a lot of data. Each of the host runs many instances of a specific process p1, which makes several scp connections to other hosts in ...
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201 views

How to find the file corresponding to a pipe opened by a process? [duplicate]

I created this script, which listens for characters received on a hardcoded pipe, and tries to eval those characters. I call my script loop_executor.sh This is all it contains: !/bin/bash while : do ...