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

learn more… | top users | synonyms (1)

13
votes
3answers
5k views

Elegantly get list of descendant processes

I would like to get a list of all the processes that descend (e.g. children, grand-children, etc) from $pid. This is the simplest way I've come up with: pstree -p $pid | tr "\n" " " |sed "s/[^0-9]/ ...
2
votes
1answer
140 views

Why does a “child” process finish before its parent?

This is the code example given: # include <stdio.h> # include <unistd.h> void main() { static char *mesg[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"}; int display(char ...
3
votes
3answers
362 views

How to create a process tree?

I have some code that kills processes and their children/grandchildren. I want to test this code. Currently I'm doing $ watch date > date.txt, which creates a process with a child. Is there any ...
1
vote
0answers
31 views

Cannot terminate for loop in terminal

I was running a for loop in terminal which has a sox command in it. For some reason the sox command failed and now I cannot terminate the for loop. I tried pressing Ctrl+c many times, Ctrl+z many ...
4
votes
3answers
138 views

Show network connections of a process

There is a way to show the connections of a process? Something like that: show PID in which show is a command to do this, and PID is the pid of the process. The output that I want is composed by ...
4
votes
1answer
83 views

Why does a process of a binary with only execute permission remain hidden in “ps” when using hidepid=2, if the user is not root?

I'm using hidepid=2 to mount /proc, so users can't see any but their own processes. A particular binary I want to use has been restricted to rwx--x--x permissions, so only its owner (root) can read it ...
1
vote
3answers
163 views

Set Parent Process ID from ShellScript, kill all Child Processes later

I want to write a shell script for my Ubuntu machine, that starts a few server applications. I need this script in order to execute it from my java application. But I need an easy way to group all ...
1
vote
4answers
328 views

Disabling column names in ps output

How to format output of ps -p command? To not show me something like this: PID TTY TIME CMD but just PIDs. I'm using Linux.
1
vote
0answers
16 views

How to stop a program that is not showing up using monit?

I have a set of raspberry running raspbian. On each of these, I have configured monit to monitor the epiphany browser, which should always show up with a specific web site. Unfortunatly, some times ...
1
vote
3answers
114 views
2
votes
3answers
62 views

Processes group (session) of GUI processes

According to what I know, the shell and its child processes are in the same session which have the same (controlling) terminal. I read that they are interactive processes because they have the same ...
1
vote
2answers
135 views

Shell's process group ID = foreground job's process group ID?

I decisively conclude that Shell's process group ID = foreground job process group ID from the 2 sources below. When a background job is selected to run in the foreground, is it the shell's process ...
1
vote
1answer
92 views

Unable to kill process, even with root. How to diagnose?

There are a lot of bash processes running on my Ubuntu Linux (12.04). Even when I close the terminal they are still shown in the System Monitor. I tried killing them as below, but they remain as it ...
1
vote
0answers
11 views

Definitions arguments of daemon and server

Somehow, I feel clear about definitions of daemon and server after learn a little bit about X11. So, I would like to have verification to my definitions as below. Daemon is a process that is not ...
1
vote
1answer
56 views

How do I get the pid of the exact progarm launched

So I have a couple python programs say program A and program B, when using "pgrep python" to get the pid, it gives me the pid of both program A and program B. However, I am writing a program that need ...
2
votes
2answers
93 views

When does a process terminate in UNIX?

At which moment a process in Unix is terminated? Is it necessary a command such as exit(0) or return 0 to be written in a program to terminate a process? My question is provoked by the following code: ...
2
votes
4answers
1k views

Is there a way to identify which process turns into Zombie process

One of the ubuntu server has 82 zombie processes. All processes shows '[sh] defunct' as process command. Is there a way to find out which process is becoming a zombie process? I tried checking the ...
2
votes
1answer
46 views

Add fixed PID value to the process

I need to set PID number of my process to fixed value, because I need to kill it with my application when some conditions are met, is it possible to do that?
8
votes
1answer
7k views

What does kill 0 do actually?

In the man page, it says: kill [ -s signal | -p ] [ -a ] [ -- ] pid ... pid... Specify the list of processes that kill should signal. Each pid can be one of five things: 0 All ...
2
votes
1answer
40 views

What is the difference between opening an application from terminal Vs directly opening it?

I could open Firefox browser either by clicking FF icon on desktop or by running ~/firefox/firefox & in the terminal. What are the differences in these two ways of running? I am wondering because ...
15
votes
1answer
2k views

Why is the maximum PID in a 64-bit Linux system 2^22?

Why not 2^62, or 2^31 or anything else? What is the maximum value of the PID of a process?
31
votes
9answers
4k views

How can I kill a process and be sure the PID hasn't been reused

Suppose, for example, you have a shell script similar to: longrunningthing & p=$! echo Killing longrunningthing on PID $p in 24 hours sleep 86400 echo Time up! kill $p Should do the trick, ...
1
vote
0answers
40 views

Threads vs. Processes [closed]

What is more recommended when developing an application, which for example has to do: receive characters from UART port, parsing GSM data, website update. Is it better to distribute/split tasks to a ...
8
votes
6answers
7k views

How do I start a process with a nice value of -20 and not give it root privilege?

I would like to start a process with a nice value of -20. This requires me to use a command like - sudo nice -n -20 matlab. However, this starts matlab as root too. Is there a way to have matlab as ...
1
vote
2answers
116 views

How to start the killed java process with its PID?

How to start the killed java process with its PID in Linux?
0
votes
0answers
51 views

Per-process monitoring in cacti

I've read in some question that you are performing a per-process cpu/memory monitoring with cacti. Could you point a how-to I can use to get the same? Many thanks in advance.
38
votes
3answers
62k views

Find and remove large files that are open but have been deleted

How does one find large files that have been deleted but are still open in an application? How can one remove such a file, even though a process has it open? The situation is that we are running a ...
2
votes
3answers
107 views

How to find out the process(es) that forks a lot?

Recently I got an load-too-high issue on our server. I watched top for like half an hour to find out that it was Nagios that forked a lot of short-lived processes. After bouncing Nagios, everything ...
2
votes
3answers
2k views

How to monitor use of Huge Pages per process

I'm trying to determine which process is using a large number of Huge Pages, but I can't find a simple Linux command (like top) to view the Huge Page usage. The best I could find was $ cat ...
8
votes
4answers
3k views

New parent process when the parent process dies

In UNIX, when a parent process disappears, I thought that all child processes reset init as their parent. Is this not correct all the time? Are there any exceptions?
6
votes
4answers
14k 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 ...
3
votes
1answer
61 views

Can I exec an entirely new process without an executable file?

Suppose my non-root 32-bit app runs on a 64-bit system, all filesystems of which are mounted as read-only. The app creates an image of a 64-bit ELF in memory. But due to read-only filesystems it can't ...
1
vote
3answers
59 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 & ...
2
votes
2answers
199 views

Thin LVM pool frozen due to lack of free space, what to do?

My thin LVM pool got full and some programs hung: device-mapper: thin: 253:4: reached low water mark, sending event. device-mapper: thin: 253:4: no free space available. INFO: task jbd2/dm-6-8:742 ...
1
vote
1answer
44 views

List of killed apps

Is there a command to list latest killed processes? Or to search through log file for killed app, for example called "my_app"?
14
votes
4answers
13k views

Why is SIGINT not propagated to child process when sent to its parent process?

Given a shell process (e.g. sh) and its child process (e.g. cat), how can I simulate the behavior of Ctrl+C using the shell's process ID? This is what I've tried: Running sh and then cat: ...
1
vote
1answer
62 views

Figure out the PID of exact node.js application

Here is an output of my ps aux: ps aux | grep "node" root 2501 0.0 3.4 720400 68512 ? Sl 16:09 0:03 node /etc/skbx/host/skbx.js 8081 tula13 8082 8084 8085 10.8.0.6 root 20586 ...
0
votes
1answer
56 views

Haveged service won't run (dead pid)

So my system entropy is low on my centos 6 VM. (137) and I installed haveged, Yum install haveged But when I go to start the process it instantly dies: Process is dead but sub system is locked ...
2
votes
2answers
117 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 ...
3
votes
1answer
121 views

How to kill a task that cannot be killed (uninterruptable?)

I have a task running that blocks pm-hibernate (on Linux 4.0.7-2). When I try pm-hibernate there is an error message "Freezing of tasks failed after 20.002 seconds (1 tasks refusing to freeze, ...
2
votes
0answers
48 views

When waiting on a pagefault, in what kind of sleep is a task?

Are tasks put into interruptible/uninterruptible/killable sleep when waiting on a pagefault? Does it matter, what kind of pagefault is it?
3
votes
2answers
157 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?
0
votes
1answer
159 views

nginx stop is not working and nginx is creating new process after killing processes

nginx version: nginx/1.8.0 I am trying to stop nginx with the following command /etc/init.d/nginx stop, however it is not returning any successful message. Then I tried to view the nginx processes ...
0
votes
0answers
19 views

most minimum processes required to have Linux that functions properly [duplicate]

If I want to have Linux that functions properly for a user, are the most minimum processes required are init/systemd, terminal emulator and shell?
1
vote
1answer
43 views

My compiled program is being run via init.d but eventually gets killed

I made a small utility application in C that monitors udev for power events and adjusts my laptop backlight brightness automatically. (I'm running Ubuntu 15.04) I ran the following commands and it ...
2
votes
0answers
39 views

Detect which program is blocked by firewall

The linux firewall can show a lot of information in the LOG target, for example via --log-uid. How can the executable doing the network call be logged, too? I did not find anything in the FAQ, the ...
2
votes
2answers
2k views

Why doesn't stopping the nginx server kill the processes associated with it?

When I stop nginx like this on ubuntu 12.04, I get the following errors: $ sudo service nginx stop Stopping nginx: nginx. $sudo service nginx start Starting nginx: nginx: [emerg] bind() to 0.0.0.0:80 ...
0
votes
1answer
130 views

List process by name excluding grep [duplicate]

I am trying to list all the ffmpeg processes that are currently running on Debian machine (Ubuntu 15). I use the following command: ps aux | grep 'ffmpeg' If only one ffmpeg process is running, I ...
11
votes
3answers
2k views

Make a process unkillable on Linux

I'm working on a password manager application, and for security reasons I want to launch an unkillable process. And besides I don't want this program to be a daemon since I need to read from standard ...
3
votes
2answers
46 views

Alternating a long running task to pause/run to reduce cpu

I have large file I need to mv and even with nice -n19 it seems to affect the server performance. I think an option would be to run the process in "chunks" whereby I run the command for a few ...