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

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Hook action on process creation

Is it possible to hook a script execution on each process creation? Essentially the equivalent of inotifywait to monitor disk activity but applied to the process table. It would be to allow to do an ...
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49 views

What is the default memory allocation for shell process by linux

What is the default memory allocation for shell process by Linux , i mean is there any upper limit for shell process or any process.
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1answer
53 views

Possible to identify defunct process from pgrep

I am using pgrep for a bunch of things, however I can't get pgrep to list if the process is defunct. Running ps adds to the end of the item <defunct> but pgrep does not, is there anyway to do ...
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1answer
129 views

cpu usage is 100% but top doesn't show any process using it

First of all, I forgot to save the process list. I had to reboot the server so I can't give much information. I have a small VPS. The cpu usage was 100% in both top and in the control panel graphs, ...
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3answers
63 views

How do I get the first branch PID of an application in pstree command?

I want to get PPID of chromium browser. When I launch chromium-browser it launches many child processes with the same name. For example: $ pidof /usr/lib/chromium-browser/chromium-browser 8963 ...
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4answers
41k views

How to attach terminal to detached process?

I have detached a process from my terminal, like this: $ process & That terminal is now long closed, but process is still running and I want to send some commands to that process's stdin. Is ...
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0answers
21 views

Pipe output of process that's already running

I've got a process that spews out a lot of output, and it's going to be running for the next hour. I forgot to pipe its output through my awk script before I started running it. Now my terminal is ...
259
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12answers
234k views

What if 'kill -9' does not work?

I have a process I can't kill with kill -9 <pid>. What's the problem in such a case, especially since I am the owner of that process. I thought nothing could evade that kill option.
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How to get the pid of the last executed command in shell script?

I want to have a shell script like this: my-app & echo $my-app-pid But I do not know how the get the pid of the just executed command. I know I can just use the jobs -p my-app command to grep ...
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2answers
72 views

How do I kill a process given its “command”?

I have a process called "P1", right now the way I kill the process is: $ ps aux | grep "P1" " Now it returns two processes related to "P1": one is the actual P1 process I want to kill, the other one ...
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1answer
36 views

Kill command also kills other process

I have a very simple script, let's call it foo.sh. It's this: #!/bin/sh sxhkd & panel & where panel is a script (I won't post it here because it's very long and I don't think it would be ...
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3answers
113 views

Process scheduling data on linux

I am doing a project on OS and require the process scheduling data for an operating system. The data has to include the list of all processes in short-term-scheduler and long-term-scheduler along with ...
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2answers
74 views

How to “track” newly created processes?

I know that with ps I can see the list or tree of the current processes running in the system. But what I want to achieve is to "follow" the new processes that are created when using the computer. As ...
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2answers
52 views

How to prevent a process from hanging the computer?

A process can cause the computer to "freeze" for example when exhausting CPU or swap. Is there a way to prevent this from happening? For example by setting the max %CPU or IO MB/s that can be granted ...
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0answers
54 views

RAM not used by process? Then who uses it? [closed]

I don't understand who uses my RAM. I can see clearly that it's used, but I have no ideea who uses it. Do you have any ideea what could be wrong here? I'm experiencing random spikes of high memory ...
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1answer
103 views

Kill a running shell script, and kill all process running within it

I have a shell script running in the background, which runs 5 different jobs. When I run the shell script all 5 jobs start running in order. When I kill this shell, whichever process is running, will ...
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0answers
11 views

What is the equivalent of pstop on OSX?

Is there an equivalent of pstop in OSX? How is pstop different to kill?
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2answers
113 views

From bash, spawn two processes and exit both if either sibling exits

From bash, I am spawning two processes. These two processes depend on each other. I want both to exit if either one dies. What is the cleanest way to do that? Currently I have the following: # start ...
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1answer
171 views

Weblogic process just killed suddenly on redhat linux

One of the process on my WAS killed at dawn. 6 process run on this server. But only one process just killed. I don't know how to fix it. This is Weblogic last log that before process killed. ...
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1answer
112 views

The sum of % in the CPU column doesn't match the total CPU % row [duplicate]

I don't understand why the sum of % in the cpu column in top doesn't match the total CPU % row: Text version with slightly different values: ubuntu@server:~$ top top - 23:20:21 up 5:18, 3 users, ...
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1answer
40 views

What happens to a process handle when the process has stopped?

If I have a handle of a process and that process has stopped, Do I need to close the handle? Can I use the handle to rerun the process? Can I use the handle to find out information about the ...
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3answers
56 views

Process in Unix

When I log into my unix terminal and just do ps: bash-4.3$ ps PID TTY TIME CMD 7 pts/0 00:00:00 sh 16 pts/0 00:00:00 bash 17 pts/0 00:00:00 ps I know bash process is ...
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1answer
49 views

When is a port considered being used?

I am getting port in use cannot bind on process restarts. I am trying to find out when a port is considered being used? Is it only when in LISTEN mode? Can it also be if a connection is open to the ...
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1answer
63 views

How do you tell what the return code of a process is when it exits and where is the value usually documented?

If a process runs and exits it returns a non-zero status (personnaly I prefer the term return code); or even a zero status I know that the value is there (mostly because I've done C++ programming and ...
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1answer
51 views

Downsides of processes with high virtual size but low RAM and GPU memory use

I have noticed that some of my processes take a lot of virtual size in my computer. I understand that the virtual size of a process is the sum of memory it is actually using, memory it has mapped into ...
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27k views

What does this process STAT indicates?

If you check the STAT column in above image you will see Ss S S< SN and R+ What does this indicates ? Process states. If yes,Then what is the significance of 'Ss S< SN and R+'?
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85 views

Why does killall command kill only one instance of the process?

Sometimes I need to kill Google Chrome (of which I have 2 windows/instances opened). Both instances are not in incognito mode. What I do is: (on Debian 8) killall chrome && killall chrome ...
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1answer
69 views

Is forcing an application to release some the allocated memory possible?

Ever since I came back to Firefox a year or so ago I have been facing the same issue over and over again - the browser just keeps eating up my memory. The problem arises from (maybe the incorrect ...
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1answer
1k views

Change the parent process of a process?

Is it possible to change the parent process of a process? If yes, how? For example, how does screen manage to attach a screen session and the processes running inside it to different shell ...
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1answer
124 views

Is it possible to add a process to the job list in bash (e.g. to reverse “disown”)?

If I disown a job in bash and change my mind, can I undo it somehow ? If so, taking it further, is it possible to bring an arbitrary process under job control (an acceptable restriction would be that ...
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4answers
6k views

What happens to the output of a process that has been disowned and lost its terminal?

If I close the virtual terminal, where some process was started, does the output just go straight to /dev/null, or can it pollute memory somehow? Can I anyhow grab the output to continue reading it at ...
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1answer
27 views

Get PID of scheduled job (using at)?

Say I want to schdule this job to be run at later time MYPROGRAM > output.out 2> error.err | at 02:00 PM Mon How can I attain its PID? surly using: echo $! will not work?
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1k views

'htop' process and threads cpu usage?

I'm observing a multi threaded process in htop in tree view. If I were to strip it just to the problematic part, it looks somewhat like this: CPU% bin/process 100 `- ...
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What happends when sending SIGKILL to a Zombie Process in Linux?

In Linux, when a child process terminates and it's parent has not yet waited on it, it becomes a zombie process. The child's exit code is stored in the pid descriptor. If a SIGKILL is sent to the ...
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1answer
72 views

How to run command in foreground then send to background

I need to run my application in foreground of linux terminal, send some commands to my program and then send program to background. I'm not really sure how to do that?
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1answer
87 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
59 views

Schedule a job to run in the background ( one time task scheduling using at )

Is it possible to request for a job to be run at a later specifed time in the background? This is what I have so far, nohup nice MY_PROGRAM > foo.out 2> foo.err < /dev/null | at 05:23 PM ...
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1answer
37 views

what happens to remotely run process when remote host disconnects?

Say, I ssh into a remote host, initiate few processes on it and disconnect before the processes terminate. What happens to the processes? Do they continue?
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7answers
106k views

Is there a way to see details of all the threads that a process has in Linux?

For Windows, I think Process Explorer shows you all the threads under a process. Is there a similar command line utility for Linux that can show me details about all the threads a particular process ...
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3answers
157 views

How to wait for all spawned and backgrounded processes to finish in bash script

I've looked and looked and can't find a working solution to a bash script I'm trying to create to shut a process down and wait for it and spawned processes to finish. I'm still learning a lot of ...
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2answers
523 views

How to wait for the copying process (cp) to finish?

I want my RPi 2 (with MiniBian (a minimal version of Debian-based Raspbian OS) as its OS) to execute a script when it detects a USB flash memory is inserted. So this is what I have done: I created ...
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1answer
39 views

Linux applications, user and system

I was wondering if there was any CLI command that would allow me to see what applications are being run by the current user, but ones that are not system commands. for example if I run lsof it will ...
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27 views

Real-time monitoring of changes in swap use (per process)

I'm looking for a way to observe which processes in my system are consuming an increasing amount of swap over time. The following function generates a list of swap user per process : sbp(){ grep ...
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2answers
58 views

Sleep system call and its time parameter

Let's say that we are writing a C program that calls the sleep() function. For instance, by calling sleep(7), the calling thread would be put to sleep for 7 seconds. My question is: Will the thread ...
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1answer
88 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 ...
4
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1answer
123 views

Pulling all of a process's swapped memory out of swap

How would one go about quickly pulling all of a process's swapped memory out of swap without writing to disk? The context on this issue is trivial, as the systemic issue necessitating the question ...
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2answers
47 views

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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1answer
57 views

Can I set a resource limit for the current process tree?

Let's say I'm running on a resource-constrained system, and I want to ensure that the applications I run open no more than 10 files total. If I try to do it using setrlimit, something like: if ...
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177 views

Why does running sudo cp show two processes

I am trying to copy some files and folders on a Centos machine. I do it like so: sudo cp source destination & to run it in the background. I see there are three cp processes now when I run ps ...
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How does the Linux scheduler determine if a process is I/O bound or CPU bound

Adding to this question, how does the scheduler determine if a process is I/O bound or CPU bound? Mr. Love in this article, says "schedulers often employ complex algorithms to determine the most ...