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

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Can Process id and session id of a daemon differ?

As far as I understood from different articles and here , a daemon has the following features: Parent Process ID should be 1. No terminal should be associated with the process. The process id, ...
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17k views

Modify 'Soft Limit' of 'Max processes'

I tried ulimit -u 2000 and ulimit -Su 2000 to modify the 'Max processes', and started up my program, but failed. I found file '/proc/pid/limit' is still: Max processes 1024 ...
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Is reparenting from the shell possible?

This question is closely related to How to "correctly" start an application from a shell but tries to tackle a more specific problem. How can I spawn an application from a shell and thereby ...
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3k views

Simulate an unkillable process in D state

For catastrophe testing scenarios on out server environment we're looking for an easy way to make a process stuck in D (uninterruptible sleep) state. Any easy ways? An example C sample code would be ...
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2answers
1k views

How can I allow a user to prioritize a process to negative niceness?

I want a user to run a specific process on the system with a negative nice value. I can't simply fork the process to background as this specific program is a minecraft server and I rely on the command ...
6
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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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4answers
30k views

How to kill a process which can't be killed without rebooting?

There are 5 processes which can't be killed by kill -9 $PID and executing cat /proc/$PID/cmdline will hang the current session. Maybe they're zombie processes. Executing ps -ef or htop will also hang ...
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4answers
16k views

Bash script wait for processes and get return code

I am trying to create a script which will start many background command. For each background command I need to get the return code. I have been trying the following script : #!/bin/bash set -x ...
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1answer
106 views

PID in arch-chroot is incorrect

I am trying to run a python script in a chroot (specifically, the chroot is created with arch-chroot). The python script relies on os.getpid(), but this seems to be returning an incorrect PID within ...
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598 views

How can you change the process name of Wing IDE from python to something more descriptive

In my process list under Ubuntu (using top/System Monitor) one of the largest memory hogs (200+Mb) was python. I searched a bit for one of my programs to be the cause until I realised this was my ...
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1answer
8k views

What is kondemand?

I have searched the web for the answer of this question but couldn't find a clear answer. Best answer I found was as follows: kondemand is a kernel thread that belongs to the ondemand governor of ...
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4answers
625 views

why new pid is smaller than the old ones?

Is there any chance the new process's pid is smaller than the existed ones ? I have a daemon process which will restart when be killed, I recorded the pids, and found that the pid first came smaller, ...
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3answers
109 views

How to get the pid to the last background app

Following from this question: How to get the pid of the last executed command in shell script? The thread there is good and clear, but what if the command actually doesn't require a '&' at the ...
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2answers
721 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 ...
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4answers
848 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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1answer
647 views

bash: disable new process PID message

It may look like this: [2] 2847. I guess the first digit is just an enumeration of processes created from the shell. The second is the PID. Anyway, I never care about that information so it is just ...
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2answers
56 views

When opening a terminal does not require a login?

Speaking about Linux and in particular Ubuntu (from 14.04) systems: Case 1 - As pointed out in this answer, processes that allocate a pseudo-terminal don't need to make a login: for example, cups. ...
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3answers
86 views

How to make init script print “OK” only when all subprocesses are stopped?

I have a very complex python application. It has it's own init script, but when I execute: sudo service my_service_daemon stop It prints "Stopping my_service_daemon [OK]", but in real ...
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2answers
169 views

Why do multiple instances of Mate-terminal have the same PID?

I've noticed, that all mate-terminal instances I start, be it inside a mate-terminal or via a link button, have the same PID. For example, I got something like $ wmctrl -lp <omitted lines that ...
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2answers
1k views

How can a process appear to have different name in ps output?

recently I had to clean up a hacked server. The malicious process would appear as "who" or "ifconfig eth0" or something like that in "ps aux" output, even tough the executable was just a jumble of ...
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3answers
686 views

how to run the dialog command with proccess

Please look on my code – ( bash script ) I want to display both dialogs on the screen on the same time, one dialog display the: tail –f from - /var/log/proccess1.log , and the second dialog ...
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0answers
150 views

CGroup Processes Not Terminated even when main process has been killed through Systemctl stop command

I am running systemctl stop process command for some process. Please find the output for systemctl status process below: Loaded: loaded Active: deactivating (stop-sigterm) CGroup: ...
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1answer
3k views

How is it that I can attach strace to a process that isn't in the output of ps?

I'm trying to debug why our integration tests are taking so long and it looks like they're hanging part way through. I logged onto our test service and saw the following behaviour: root@colossus:~# ...
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2answers
518 views

How to get environmental variables of a very short process?

I have a very short process for which i want to check the environmental variables for debugging purposes. The process is instant from a human perspective. The example illustrates it better. Example ...
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2answers
3k views

“ps” command doesn't return to prompt

I have this linux box that I need to maintain periodically. To do that, I issue a ps command programmatically and check the running processes. But as shown in the screenshot, sometimes, the ps ...
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1answer
72 views

Are kernel threads processes and daemons?

From Mauerer's Linux Kernel Architecture, Kernel threads are processes started directly by the kernel itself. They delegate a kernel function to a separate process and execute it there in ...
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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
61 views

Strange behavior with bg command

How to send process (application) to background if it always expects input on terminal and sending received data from uart to stdout all the time? I cannot send my app to background with CTRL+Z & ...
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2answers
185 views

start process (as root) upon user login

I would like to start a process as root upon each user login. The motivation beside this is, that the process will work on encrypted home folder of particular user folder. How can I achieve this?
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291 views

Are there any alternatives to pidof? (smaller footprint)

Well, I've just found out that with extensive usage of pidof in very short intervals, the seemingly tiny tool can be a great CPU hog. (Source: top) On my older machine, it can easily reach 30 percent ...
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3answers
468 views

How can I get the pid of a process started this way

#!/bin/bash mkfifo /var/run/out while true do cat /var/run/out | nc -l 8080 > >( while read line do do some stuff done ) done How can I get the pid ...
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1answer
345 views

How to find out a process gets end?

How can I tell when a given process exits? Like when it's done running and stuff. For instance: # Command 1 wget http://releases.ubuntu.com/14.04/ubuntu-14.04-desktop-amd64.iso # Command 2 echo ...
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3answers
405 views

How do I start a server via ssh and have it run after I log out?

I ssh into a virtual server and start up a web server. Everything runs as expected. But when I close my terminal on my laptop, the process dies on the virtual server. How do I fix this?
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How to kill a script which starts new processes?

The following is a Python application which spans a few threads, then spawns a new process of itself and exits: $ cat restart.py import os import random import signal import sys import threading ...
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2answers
1k views

Invoke a command/script disconnected from the controlling terminal?

I'm investigating the behaviour of a script that is normally run as an automated process (e.g. cron, Jenkins). The script can (eventually) invoke commands that behave differently (seeking user input) ...
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1answer
204 views

Alert when a process exits

I often download files using wget and cURL. Is there anyway I can make my Linux box give a visual alert when either of those processes exit (i.e: the download completes) PS : I am using Ubuntu ...
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2answers
134 views

Terminal command (called not from SU) that would restrict process from writing to all directories but one?

We have an app testApp. We have a folder called notRestricted in the directory where we run app from. We want to limit access of the app to file system so that app could write only to that folder (we ...
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1answer
36 views

Process login vs user login

In a Ubuntu 14.04 system, who has the following output: user1 :0 2016-05-02 14:49 (:0) user1 pts/4 2016-05-02 15:10 (:0) So apparently just the pts/4 is used. But, for example, ...
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1answer
43 views

How can I pause or freeze a running process? [duplicate]

I would like to pause/freeze a process in time; how can I do that? Not duplicate because kill -STOP <PID> has caused applications to crash when I've used it.
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77 views

history/log of command-lines executed to launch processes(pid) [duplicate]

Given a certain PID, is it possible to discover what command-line executed this process? top, atop, ps provide real time informations, I'm looking for something whereby I can look the past, because ...
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511 views

What determines if an executable can be run in different independent processes simultaneously?

I posted a question about how to run an executable (a PDF viewer) under wine independently in multiple processes (independent means no communication between them, it is not parallel computing). I ...
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2answers
264 views

How to trick an application to run different processes?

I am running PDFXCview.exe (for pdfxchange viewer portable version) under wine to open a pdf file, by PDFXCview.exe 1.pdf When I do the same for another file, the other file will be opened by the ...