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

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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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0answers
131 views

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 ...
2
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2answers
398 views

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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3answers
493 views

Why does a default Linux installation run more processes than a default OpenBSD installation?

If I ps -aux on Ubuntu (or any GNU/Linux distribution) without GUI I see ~100 processes running. If I ps -aux on OpenBSD without GUI, then I get ~10 processes. What is the explanation/reason for ...
2
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2answers
158 views

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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2answers
75 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 ...
2
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2answers
659 views

lsof for a specific process?

There's a bzip2 process running in the background and I have no idea where it came from. It's eating up a lot of resources. Can I do a reverse lsof to see which files are being accessed by this ...
2
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2answers
82 views

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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4answers
818 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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3answers
3k views

What is the difference between ps and top command?

What is the difference between ps and top command ? I see that both can display information about running processes . Which one should be used when ?
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2answers
2k 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, ...
2
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2answers
105 views

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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4answers
780 views

How to send keystrokes (F5) from terminal to a process?

I'm using an Raspberry Pi in combination with Chromium (kiosk mode) to show up some stats. The Pi doesn't have an connected keyboard so I searched for a solution to send keystrokes from the terminal ...
2
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2answers
2k views

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?
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2answers
528 views

Is there any impact of reaping zombie processes?

I will execute following command for reaping zombie /usr/bin/preap $(ps -ef | grep defunct | grep -v grep | awk '{ print $2 }' | xargs) Is there any service impact of this approach ?
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5answers
2k views

How to stop a program running as daemon

I have launched iperf in daemon mode with iperf -s -D and now I want to stop the service. I tried to use sudo kill pid but it neither work nor complain. The daemon is still running when I check ...
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3answers
2k views

pkill can't kill processes with parent process id 1

I want to kill the following processes using pkill "run_tcp_sender.sh" or pkill -SIGKILL "run_tcp_sender.sh" root 14320 1 0 2012 ? 00:00:00 bash run_tcp_sender.sh ...
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1answer
4k views

How to find Heap memory of a running process? [duplicate]

I would Like to know how to find the heap captured of a process which is running in the background? Is there any command by which you can find the process heap memory and here the process is still ...
2
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3answers
981 views

Why does Firefox refuse to die despite killing it with pkill -9?

I am issuing the following command to kill Firefox on my Red Hat Linux box: [subhrcho@slc04lyo ~]$ pkill -9 -f firefox [subhrcho@slc04lyo ~]$ However, when I try to invoke Firefox through ...
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3answers
2k views

How does the set-user-ID mechanism work in Unix?

Can someone please explain the set-user-ID mechanism in Unix ? What was the rationale behind this design decision? How is it different from effective user id mechanism ?
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5answers
1k views

How to get a process uptime under different OS?

Under Linux I can get a process's uptime in seconds with: echo $(($(cut -d "." -f1 /proc/uptime) - $(($(cut -d " " -f22 /proc/$PID/stat)/100)))) But how can I get it under different OS? ex.: ...
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3answers
1k views

How can I test if a program is running from within a script

Let's assume that another user started a bunzip process, and I have a script that I'd like to start running after that bunzip finishes. What's the best way to check from inside my script that the ...
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1answer
1k views

A more readable ps

Are there any tools that improve the readability of ps in the same spirit as ack for grep? This would be especially on OS X where ps does not even have options such as --sort user. So far the nicest ...
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2answers
115 views

How can I get the version of the pgrep & pkill commands?

I looked at the manpages and there is no -v or --version argument for pgrep or pkill. How can i get some info on the version? I'm asking because on my version of Ubuntu man pgrep is giving me a ...
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2answers
132 views

a handy tool to measure memory consumption of a program [duplicate]

I develop a C code on Debian. I am looking for a program to monitor memory consumption of my code in real-time. The only value I care is the maximum RAM consumption, it should hold the value even if ...
2
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1answer
2k 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 ...
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2answers
913 views

Find the PID of top CPU/MEM usage, save to a shell variable

Is there any way to get the PID of the top CPU/MEM usage, I need to use that in a script, top command doesn't seem to work for it.
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2answers
247 views

Quick and dirty way to run a process more than once

I am looking for very simple bash script that would allow me to launch a process a few times. What's essential to me is that after the processes terminate, everything will clean up automatically. ...
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3answers
629 views

What is meant with terminating a process normally?

In an examination it is stated: Give 2 different ways that a process can terminate normally. Describe the differences. What is meant with terminate normally?
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2answers
1k views

Killing a running process in an Ubuntu machine remotely from a windows machine which is in LAN

Is it possible to kill a process running in an Ubuntu machine from a Windows (XP) machine remotely connected via LAN? I can kill the process in a windows machine from a remote windows machine (in ...
2
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2answers
115 views

How can a normal user trigger a root cron task to execute immediately, without delay?

I have a root cron task that runs every day. But I want to allow normal users to request that it run immediately, if they so wish. It is a harmless process and it can run as often as needed and these ...
2
votes
1answer
109 views

Which system calls could create a new process?

When executing ps command in my Linux system i see some user processes twice (different PID...). I wonder if they are new processes or threads of the same process. I know some functions in standard C ...
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4answers
254 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 ...
2
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1answer
397 views

what is the structure of a linux process? [closed]

what is the structure of a linux process? In linux there are processes executed on a address and which use system resources. Can anyone tell me the structure of a process and which parameter ...
2
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2answers
118 views

what happens when a window manager is put to background

I am trying to understand the situation why .xsession file expects the last process to be in foreground otherwise it is supposed to stop X11 session. I have a small stand-alone script. when I run ...
2
votes
4answers
145 views

How to find out what is this process for?

I have this 'java' process running for 3 hours ( I guess ). I didn't see it before and I wonder how could I find out where it's coming from? Here is a screenshot: EDIT: ok I figured it out, it's ...
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2answers
119 views

How to constrain the resources an application can use on a linux web server

This is the situation: I have a PHP/MySQL web application that does some PDF processing and thumbnail creation. This is done by using some 3rd party command line software on the server. Both kinds of ...
2
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1answer
543 views

using pidof with sh -c

I was wondering why this command line does not print pidof sh $ sh -c "var=`pidof sh` ; echo \$var; ps -H" This one prints 123 as expected $ sh -c "var=123 ; echo \$var; ps -H" I am on ubuntu ...
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2answers
647 views

Removing zombie process from the process table

Can somebody please explain when parent process receives the exit status of a dead child process via wait, who actually reallocates the memory of the child process and removes it from the process ...
2
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2answers
32 views

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 = ...
2
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2answers
33 views

Limitng number of process by name

is it possible, to limit number of process for given group or user using process name? Eg. I'd like to groups remotes have only 5 simultaneous ssh processes that are run on my server. I don't see any ...
2
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1answer
88 views

There are stopped jobs (on bash exit)

I get the message There are stopped jobs. when i try to exit a bash shell sometimes. Here is a reproducible scenario in python 2.x: ctrl+c is handled by the interpreter as an exception. ctrl+z ...
2
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2answers
41 views

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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4answers
93 views

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 ...
2
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1answer
78 views

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?
2
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2answers
67 views

Detecting Kernal Thread on Older Kernel Version

Looking at the proc man page (http://man7.org/linux/man-pages/man5/proc.5.html) it is possible to detect which processes are kernel threads in /proc/<pid>/stat by looking at the flags value ...
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2answers
94 views

Absolute path to currently-running zsh?

Sometimes the output of ps -p $$ shows the absolute path to the currently-running zsh, % ps -p $$ PID TTY TIME CMD 1027 ttys005 0:00.11 /usr/local/bin/zsh but not always: % ps -p ...
2
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1answer
213 views

How to see process created by specific user in Unix/linux

I want to see list of process created by specific user or group of user in Linux Can I do it using ps command or is there any other command to achieve this?
2
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1answer
440 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 ...
2
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4answers
195 views

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 ...