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

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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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101 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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1answer
814 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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1answer
19k views

How to check which process is using most memory

When I check free in one of Prod server it showing 70% of memory is being used: total used free shared buffers cached Mem: 164923172 141171860 23751312 ...
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1answer
147 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 ...
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1answer
225 views

strace works for some builtin commands

I'm trying to understand some kernel level concepts in Linux. I was checking on the difference between shell builtin commands and the other executable commands. This wonderful answer clearly tells ...
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2k views

Find the PID's of all threads of a process without ps or pidof

So the system I'm working on (BusyBox) has a ps that takes no command line arguments and pidof returns nothing even though it exists within /sbin and points to killall5. Another issue I had is that ...
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93 views

What information about a process is retrievable after it is terminated?

After a process has been terminated, is it possible to retrieve any information about it, such as when it started and finished, &c. Is it possible to enable logging of this information?
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1answer
946 views

Linux: How to check whether a process is slowed down by other running processes

I have one process running on a RHEL 6.3 machine. Somehow this is taking a longer processing time than the same process running on another machine. How is it possible to know why this process is ...
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1answer
3k views

Cannot kill a java process

I have a java process that cannot be killed. I have tried every method I know, or that I have found on the internet to no avail. I have tried: killall java kill -9 <pid> kill -11 <pid> ...
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1answer
2k views

Program stall under user but runs under root

I am running R job under a normal user john and root. Interestingly, the program stalls under john user but runs quickly under root. Using strace, I found that when john runs the R, the process stalls ...
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180 views

how to disallow user to change process group

Is it possible to restrict a process from changing it's process group? For example, user nobody seems to be able to call setpgid(0, 0) which sets process group of current process to pid of that ...
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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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3answers
330 views

How do I see more of the command line with the KDE System Guard Process Table

I often have several java programs running and I can't tell which one needs to be killed. The command section of the process table only shows java, but doesn't tell me which jar or class files it is ...
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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 ...
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65 views

How to start two processes piggie-backed? So the first finishes when the second finishes?

I'm running a script with ssh commands to a server behind a jump-host. Each time I want to run a command on my server in the secure network, I need to ssh into the jump-host (bastion) server and run ...
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1answer
83 views

Resource (CPU time and memory) limitation and termination of a process upon violation in Linux

The problem: Given a process, limit the resources it and its child-processes can use. I.e. set CPU time and virtual memory quotas. When the process group exceeds one of the limits, terminate it, ...
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85 views

Sum the memory usages of all the processes of a program?

How can we sum the memory usages of all the processes of a program? For example, I have opened many Chrome tabs for webpages, and each tab runs a different process. How can I get the total sum of ...
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103 views

How to update user/group settings of a running process?

Suppose I change some user settings like its initial login group or add it to a new group. I now can do su user and work with these new settings. But all the previously running processes will still ...
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2answers
926 views

Does jps lie? If not, what else is this?

I am running dockerized hadoop cdh 4.6.0 with supervisor . I have opened the docker container and tried the following two commands. Got confused a lot. jps 103 -- process information unavailable ...
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1answer
160 views

Identify in which screen instance a process is running

A process listening on port 8113 (Solr) is not responding. I've found its PID via netstat but the server has about two dozen Solr process running in various screen sessions. 3607.foobar-client2 ...
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1answer
130 views

Retrieve X11 window ID of a just-launched GUI-program

I want to retrieve the X id of GUI programs I launch in background, in order to work on their windows properties. I've been so far using this workaround: myprogram & sleep 1 winID=$(wmctrl -l | ...
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247 views

Why does the 'user' and 'sys' time vary on multiple executions?

There is a nice question and answer explaining the relationships between 'real', 'user' and 'sys'. It explains the reasons why 'real' can vary, and defines the 'user' and 'sys' as times the process ...
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81 views

Is each process considered a thread?

Is a Linux process considered a thread? For example, if I write a simple c program that calls pthread_create to create a new thread in main(), does that mean that I now have 2 threads, one for ...
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143 views

What is the rtsbpp-polling process doing?

In Ubuntu 12.04 LTS when I run the top command I see a process called rtsbpp-polling. Googling it gives only just a few hits to the Gentoo Linux forum that does not seem to be relevant (they don't ...
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1k views

When do jiffies increment? How a process runs in a jiffy?

I know that jiffies length is selected at kernel compile time and it is defaulted to 250 (4ms). Source: man 7 time - The Software Clock, HZ, and Jiffies I wonder what happens inside a jiffy. What are ...
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How do I detach a process from its parent? [duplicate]

Possible Duplicate: How can I disown a running process and associate it to a new screen shell? The problem is that the process is not a job inside of my active shell (as I've logged in from ...
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1answer
1k views

Limit process resource consumption in CentOS 5 (2.6.18 kernel)

I would like to limit the resource (CPU, Memory, and network bandwidth) consumption of processes on the same server. And it will be good if I can migrate processes from one server to another. I ...
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How to trace a process to original user?

Say, on a Solaris server, user1 logs in, switches to someother user, say sruser, using su - and then starts a process of id X. And then another user user2 logs in, switches to sruser the same way and ...
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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 ...
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58 views

Parent restarted by child doesn't respond to CTRL-C

I wrote a program. It starts a process (call it A) that spawns a child process (call it D) that shutdowns and restarts A. Problem is, now I can't kill A nicely from the terminal (ie. CTRL-C isn't ...
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Kill a whole process tree regardless different GIDs

I am having issues with process control using the signals available to the process abstraction. In the example below you can see there is a perl script which is the parent of the whole tree with a ...
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Discrepancy between reported used memory and sum of application memory usage

I'm running a desktop system that quite regularly suffers from lack of memory, this prompted me to investigate what causes the issue in the first place. Problem is, there's no single process that ...
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Can I get WCHAN from ps on Mac OS X 10.7.4?

From the manual it seems that ps -AO wchan should tell me what everything is sleeping on, but everything comes up as -. (And nwchan as 0). Did they do away with the old sleep()/tsleep() interface in ...
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609 views

Is there a way to make your process use less CPU?

I want my device to use less CPU to save battery. I have a program that uses a large amount of it. nice won't help as all it does is change scheduling when CPU is at %100, while I don't want it to get ...
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Is nohup indefinite?

If I run a program with an infinite loop with nohup, will the program run indefinitely (until the machine is reset or until I manually terminate it)?
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End process from another SSH window

I forgot to use screen and I have a task that has been running for quite some time, and I do not want to lose the saved data. Basically Ctrlc will end the task and save the data if I am on the same ...
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69 views

How to get information about files being copied to my machine by remote rsync command?

I am rsyncing a directory from machine B to machine A. rsync command is run on machine B. On machine A, what kind of information can I get about this rsync process (progress/amount of data downloaded ...
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Kill any service running at a specific port

I am trying to write a script that kills service running at a specific port. This is my script: a=$(ps ax | grep 4990 | grep java | awk '{print $1}') kill -9 $a It's a java program. This script ...
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424 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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7k views

killing a process on a remote machine when the machine is stuck

I started a very resources-consuming process on a remote server via ssh. It is an optimization problem run in MATLAB. It takes full memory and CPU. In fact, I am not even able to ssh to the machine, ...
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104 views

Process startup after boot

I know the following are ways processes get started in Linux from init.d (or similar) from shell (by user) forked by a running native daemon Is it ever possible on Linux for a process to be ...
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why “ps -ef -u root -U root” also displays user processes?

ps -ef -u root -U root Also displays processes whose user is not root (the current user). Can someone explain me why ? -u : EUID -U : RUID
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Why do I see more processes in KVM than in OpenVZ?

I've got a 512mb Centos 6 VPS running on KVM. Now another VPS from a org. I manage is running on OVZ. When I type top on the KVM one, I get a whole list of all sort off processes. But when I do this ...
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593 views

Why can't I kill this process?

Problem I would like to kill a process called raspivid (program which records videos using a Raspberry Pi Camera) but I cannot... This is how I call it: #!/bin/bash #Start recording... raspivid -w ...
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gracefully terminating processes with killall <processname>

I am using several instances (profiles) of Icedove (Thunderbird) and when I need to close all of them, I use: killall icedove According to man killall, if no signal name is specified, SIGTERM is ...
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688 views

Replace instance of process in place?

I suspect this is not doable just because of the security implications, but here's what I'd like to do. Basically we run a bash shell-script on our CentOS server that calls Program-A (in our case ...
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How to make processes not die after its parent dies?

I've been messing with forkbombs and noticed that if I just fork() processes repeatedly, killing the initial process will bring down the whole tree. This is not the case for forkbombs written in BASH ...
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Get return value of process by PID

If I have the PID of a process that was killed, how might I get the return status of the process? I am particularly interested to know if the return status was 143 (kill) or 137 (kill -9) as I don't ...
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How to tell who is connected via vnc to my machine?

How do I check how many vnc connections or different users are currently connected to my machine? Only through wireshark? And how do I kill any other users connected through vnc?