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

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Find out to which directory a process is writing?

This question is NOT a duplicate of this question Find out current working directory of a running process?, because the writing directory can be different from the working directory. For example, I ...
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How can I make a for loop starting a lot of processes?

I want to test some bug, and to do that I need to have a situation where the PID is larger than 99999. I am thinking of a bash script, a for loop. Any ideas?
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w command for the other network hosts

While the who command refers to the local machine, rwho shows the same informations about all the known hosts of the local network. Similarly, w shows informations about the users on the local ...
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find out the memory allocated for a particular process in ubuntu

Could anyone please tell me how to find out the memory allocated for a particular process in ubuntu?
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Process IDs range

On GNU/Linux system I seen only positive PIDs, but when kernel panic occured I seen info about process with PID=0. What's it? On Minix 3 I seen processes with negative PIDs. Minix is POSIX-compatible ...
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632 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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The current path of a process

Suppose I write a program, which outputs a file under a relative path (as opposed to a full/absolute path) - let's say, the current path. Then I compile it and store the executable under some dir ...
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Does this dispatcher produce zombie process?

I have such a dispatcher shell script. while read line do java TestProg $line & done < $tasklist On the zombie process Wikipedia page, it says if a parent fails to call wait, the ...
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How to configure the process open file limit of a user?

The default open file limit per process is 1024 on - say - Linux. For certain daemons this is not enough. Thus, the question: How to change the open file limit for a specific user?
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why cpulimit makes process STOPPED?

I'm running a python script which uses networkx package to run some algorithms on graphs. the script is import networkx as nx from networkx.algorithms.approximation import clique G = ...
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Processes lose attachment to shell when started via bash -x

Normally, if I run emacs & and then close the shell, emacs will exit. However, if I run bash -x foo.foo (where foo.foo is a script that runs emacs &), then emacs will remain open even when I ...
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ssh ncat keeps ncat process running after disconnect; how do I prevent that?

If I run the command $ ssh othermachine ncat localhost 10000 that opens an ssh session to "othermachine" and pipes it into an ncat process. (There's something else listening on "othermachine" port ...
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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 does a process handle the situation when it finds no memory to use?

What happens when a particular process finds that there is no memory to use? Will that process kill/restart another process to proceed their task ? Or what the process (that requires more memory) ...
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999 views

How to check if a currently running process is opened by root or user

I'm currently creating a BASH script to kill off processes. I first check if the process is running then kill it. But I would like to add a nested if to find out if that process was opened by root ...
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process memory usage

What is usually meant by the phrase process memory usage, what does this actually mean, i.e. what does this memory consist of? And what column does it correspond in ps aux output, RSS or VSZ?
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Open program as root, close root session but still program is running

When I run my backup script, first I switch to root, mount a truecrypt partition and then run the script. I've noticed that after run truecrypt as root, I can exit the root session and truecrypt ...
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185 views

Set a callback for when a certain process is spawned

The script I'm writing launches process A, which after an uncertain amount of time, launches a child process B. I need the script to execute a command C which depends on process B. But B might not be ...
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3answers
942 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 ...
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708 views

How can I manage jobs after I disconnect from my tty/ssh session?

If I ssh to a box and start a task that will take some time to complete I usually press control+z to pause the process, and then immediately type bg 1 to put run it in the background. I can then type ...
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463 views

Is there a log of past threads that are now closed?

Sometimes, I have a rogue Java process which takes up 100% of my CPU and makes it jump about 30C in temperature (usually resulting in a crash if not killed). Problem is, I can never really identify ...
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add “check if fetchmail is running” to this script

while ! postqueue -p | grep -q empty; do sleep 1 done killall wvdial this script checks if my mail queue is empty, then disconnects my modem. now i would like to add also a checking to fetchmail ...
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548 views

There is no bash indicator prompt after a forked process terminates

I am reading the book Advanced Programming in the Unix Environment. There is a test program to test the fork function. It works well in my Ubuntu. But what I confused is that why there is no command ...
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parsing process ID/names from /proc, thread IDs

When I'm parsing process IDs from /proc, obviously each thread of a process gets its own ID. And I realize that all the threads in that same process can be gathered from /proc/${pid}/task/. But my ...
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How can I make a process I start during an SSH session run after the session has ended? [duplicate]

Possible Duplicate: Keep SSH Sessions running after disconnection. I have a process which is basically a web-server, I start it during an SSH session. However, when I leave the session (by ...
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Traverse the Process Tree

I am aware that processes are organized in the form of a hierarchy. So, if I want to implement an operation which is to determine whether a given process belongs to a given sub-tree in the hierarchy ...
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How to know the source of a process in Linux?

In our firm, we are using Fedora 14. Our developers are using Python code to process documents. All are running as root. Somehow they did something and a file came inside which makes lots and lots of ...
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how to get the full command line args passed to a process on unix/linux systems? [duplicate]

I am looking for a reliable way to get the full command line args passed to a process even when these are very long. I do know about ps -f -p <pid> and /proc/<pid>/cmdline, both of which ...
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Re-enter PID 1 namespace

I'm trying to enter PID namespace that process with PID 1 is in from a process cloned with CLONE_NEWPID. I keep getting Invalid argument error. In other words, I clone a child process with clone() ...
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Is there a way to suspend an process belongs to shell A and foreground it in shell B?

I knew how to suspend one process and bring it into foreground in current shell, but I have no idea about that If I have run a process in shell A and now I want to bring it into foreground in current ...
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71 views

monitor multiple pids with top

I want to monitor memory usage for several processes and came up with a command like this: ps aux |grep -e postgres -e unicorn -e nginx|cut -d' ' -f2|for i in $(xargs); do echo $i; done 16112 16113 ...
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Controlling the environ passed to child process by bash

I am using x86_64 GNU/Linux with bash #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { system("set > setc"); // A subset of `$ ...
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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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cpulimit does not detect Node.JS process

I was able to limit python process to use only 50% CPU with the following cpulimit -l 50 -e python but when I tried to do the same for Node, and it is not able to detect the process at all. Does ...
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How to trace system calls being invoked after typing command?

This question is relevant to the question of 'what happens when we type a simple command on shell?' I posted earlier. (I thought it would be better to post it seperately. But if not, please let me ...
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Why does'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 ...
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How to renice a group of processes?

lb build can build live system image, and it invokes many processes while building the image. If I start it as below: # nice -n 19 ionice -n 7 -c 3 lb build all the children processes get the same ...
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How do I print the process name next to the process ID number in a file?

I'm redirecting results for something into a file and I also need to find the process name and ID number and redirect it to the file as well. I'm guessing the process name is the command in which I'm ...
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lsof - debug the output information

I was going through the questions of this site. In this particular question, I see the command lsof being used to list the files that are open for a particular user. I ran the below command in my ...
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child process does not inherit the pending signals from the parent after a fork system call, why?

Could anybody please tell me the reason to why pending signals are not inherited by the child process? On the other hand, the child process inherits the signal handlers and signal mask from the ...
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90 views

Run a script when a process throws stderr message

I want to "wrap" a process around another to catch stderr messages when they occur. Use Case I'm using Compass and I have to have a terminal open and see if there is something wrong. My plan is to ...
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217 views

How to demonstrate invalid PID assumptions?

It seems many programmers are happy with saving a PID to a file, and then later read and use the PID as if it was guaranteed to be the same process. It seems the general idea is that the odds are good ...
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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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529 views

Please explain the output from the jobs command

When I ran jobs command I see the following output : [1] - Suspended ./startWebLogic.sh [2] + Suspended (signal) top What does -/+ indicate in the second column ? ...
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`[java] <defunct>` with defunct children -> Any way to collect them?

Relating to question : What if 'kill -9' doesn't work? I have following situation : zombie process with threads, not collected by init : [root@Arch64]# ps auxH | grep java gwpl 569 ...
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269 views

What's the best strategy to catch mystery process?

I have running processes on my server that get killed every night at midnight. It's at work, I'm not around when it happens and I don't have remote access. The kill occurs very predicably at 23:59 ...
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How often is PSS value updated for a given process in /proc/pid/smaps

So if n processes are sharing a library L with size M then the contribution to their PSS is M/n. Now imagine one of the process terminates. So the contribution would be M/(n-1). Q1: My question is ...
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How to track file change

nsswitch.conf file always corrupts somehow. I do restore from my backup every time it corrupt. When this file corrupts, its time stamp is changing. Now I wonder if there is a way to track that file ? ...
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Check for process already running in webfaction?

I use Django framework on webfaction and have 5 different cron jobs. One of them lasts much longer than others and sometimes gets stuck (30-120 seconds or more). I have already set that cron job to ...
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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 ...