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

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Application in terminal still running but not directly accessible [duplicate]

Possible Duplicate: How to suspend and bring a background process to foreground I have kind of an odd problem which I haven't encountered before. Here's what I did: I started an ...
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923 views

What does m represents in VIRT column using TOP command

When we run top command it shows all the processes information. But under VIRT column there is m written against some values what does that m represents, is it MB . If yes then why it is only showing ...
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What's the difference between lsof and fuser -uvm

Both shows the number of files we're using. Yet they both shows different results. root@host [~]# lsof /home4 root@host [~]# lsof /home2 root@host [~]# lsof /home4 Then we got fuser -uvm /home4 ...
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ATOP shows red line vmcom and vmlim. What does it mean?

utility atop shows: ATOP - MyServer 2013/01/07 00:03:57 10 seconds elapsed PRC | sys 2.18s | user 8.33s | #proc 141 | #zombie 0 | #exit 0 | CPU | sys 21% | ...
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Killing all the process of a command except first process

I am sometimes stuck in a situation where a script/command kept in Cron runs more than once because of some reasons (the first instance is not completed fully, the second instance of the same process ...
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297 views

What should interactive shells do in orphaned process groups?

(Re-posting in unix per the suggestion in http://stackoverflow.com/questions/13718394/what-should-interactive-shells-do-in-orphaned-process-groups) The short question is, what should a shell do if it ...
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351 views

How to know which commands are executed when I do something in GUI

This is for academic purpose. I want to know which commands are executed when we do something in GUI, for example creating a folder. I want to show that both the mkdir shell command and create folder ...
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What is meant by stack in connection to a process?

From the book Advanced programming in the Unix environment I read the following line regarding threads in Unix like systems All the threads within a process share the same address space, file ...
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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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How do I monitor opened files of a process in realtime?

I know I can view the open files of a process using lsof at that moment in time on my Linux machine. However, a process can open, alter and close a file so quickly that I won't be able to see it when ...
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How to view output for ALL processes simultaneously?

I know that you can connect to various background processes to watch their console output, but is there a way to view the output of all processes at once? Likely it would scroll quickly and be hard to ...
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How to view the output of a running process in another bash session?

I have left a script running on a remote machine from when I was locally working at it. I can connect over SSH to the machine as the same user and see the script running in ps. $ ps aux | grep ...
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What is the `ucond` process state?

When debugging a program I saw that top -U username showed the following: 39769 eigenein 107 98 0 179M 38448K ucond 19 0:00 0.00% program What does it mean that a process in the ...
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222 views

What does the term static variable mean in unix speak?

From the section 2.7 of the book - The Linux programing Interface named Process memory layout : Data is defined as the static variables used by the program. What is the significance of the word ...
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What does d signify in processes like syslogd and httpd?

Why there is a "d" after the name of processes like syslogd and httpd ? What is its significance ?
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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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I want to kill all processes that result from the following command

The following command will display all the PID's running for vmstat1: ps -ef | grep "vmstat 1" | awk '{ print $2 }' My question is, how do I kill them all, if there's like 20 of them at once?
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receiving command as a parameter in bash

I have a following simple script called single-instance that executes the given command if there is no process under that command running. If I hard-code the command after the else statement, it has ...
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What's the mechanism that a process listening to localhost refuses to process a request to its LAN IP address?

The private IP address of my machine is 192.168.44.182. If I started a process using nc -l localhost 20000 Then this process won't handle requests sent to 192.168.44.182. Since the process ...
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vim not shown in fuser

First use Vim to edit a file, say /tmp/A. Assuming that vim process is the only one that accesses /tmp/A, then use "ctrl+z" to suspend the process, and execute fuser /tmp/A Then you see nothing ...
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How can I find which process sends data to a specific port?

I have a service, keeping a certain port open. I'm getting data to it, that I neither expect nor want to get, and I'm trying to pin-point the source of this data. So how can I find which process that ...
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Modify environment variable in a running process [duplicate]

Possible Duplicate: change environment of a running process Is there a trick to modify an environment variable in a running process? I need to add a repository at the end of PATH. I have ...
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remotely query text file associated with an instance of vi

I have opened several text files (a.txt, b.txt, c.txt, ...) in different sessions of vi launched from different instances of a bash shell. Having then accessed that machine remotely, I wish to ...
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Get PID of a function executed in the background

#!/bin/bash function abc() # wait for some event to happen, can be terminated by other process { sleep 3333 } echo "PID: $$" abc & echo "PID: $$" I need to retrieve the pid of this function, ...
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What's the difference between running a program as a daemon and forking it into background with '&'?

What are the practical differences from a sysadmin point of view when deploying services on a unix based system?
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Stuck process: is it a bad sign?

Sometimes a few process are in a stuck state. For example: PID COMMAND %CPU TIME #TH #WQ #POR #MREGS RPRVT RSHRD RSIZE VPRVT VSIZE PGRP PPID STATE 99357 plugin-container ...
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What process is sending TCP SYNs on Solaris 10?

Some process on my Solaris 10 machine is sending TCP SYNs to a remote machine. The remote machine never responds, so the connection is not established. How do I find out what process is initiating ...
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How to run linux process and come back to it later?

I'm trying to run a minecraft server on linux. Running the server starts an important interactive session. I can run the server in the background by appending & at the end of the command and log ...
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How to stop a infinite running process (ztail) started by a ssh session after that session is closed

I have a peculiar problem. My server supports multiple ssh session simultaneously, so that multiple admins can manage (via command line interface) it simultaneously. We have a command which calls ...
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Is there a program that can send me a notification e-mail when a process finishes?

I am a computational scientist, and I run a lot of lengthy calculations on Linux. Specifically, I run molecular dynamics (MD) simulations using the GROMACS package. These simulations can take days ...
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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 ...
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“Virtual” shell, ie. jailing an user inside a process after the (SSH) login

The title might not say much about the issue at hand so let me get straight to the point. Let's assume I have a casual user who can log in to the system via SSH into a bash shell. I also have a PHP ...
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Is there any way to attach latrace to an already-running process?

I want to trace a running multi-threaded process's library calls. As of 5 November 2012, there's only one way to get ltrace to fully support tracing multi-threaded processes: you must check out and ...
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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?
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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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572 views

Korn shell timeout/kill script

I am trying to write a simple Korn shell script to execute a loading process. The process occasionally runs into connectivity issues, so I need to kill it if it runs too long. I have been trying the ...
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Understanding ps elapsed time format for long running processes

I'm using a ps command as part of an exercise to identify processes running longer than a given threshold. I'm using the following template to get the elapsed time for a know process command: ps -eo ...
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How to kill a process giving it a number of seconds before a doing the forced kill?

I do have the PID of the process to be killed but I do want to give it the chance to die peacefully, without doing a -9. Expected behaviour: check if PID is still running for up to ten seconds and do ...
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Files bigger than max(off64_t) on Solaris, eg “/proc/../as”

How do I read or seek from a file that's bigger than the maximum off64_t? The problem arises because the address space of a process is represented in the /proc/.../as file, which is a huge sparse file ...
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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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root owned program with setuid bit on

Ping is a a program owned by root with the user id bit set. $ ls -l `which ping` -rwsr-xr-x 1 root root 35752 Nov 4 2011 /bin/ping As I understand it, if a user runs the ping process, then the ...
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Kill many instances of a running process with one command

This is one of the questions that has troubled me often. Suppose I have thousand or more instances of any process(for e.g. say the process vi) running. How do I kill them all in one single shot/one ...
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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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Silently start task in background

I know that you can use this to start a process in the background, without getting the notification when the process is put in the background and when it is done like so: (command &) &> /dev/null ...
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What is the advantage of using pthreads in Linux?

I read somewhere that Linux threads are really implemented as processes in the kernel since with today's hardware and on the Linux platform, the thread model is inefficient compared to the process ...
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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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How to poll existence of a background script correctly

I have a problem with the following kind of script: #!/bin/sh long_running_script.sh & while [ `pidof long_running_script.sh` ] do echo "." sleep 1 done The sript will ...
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2answers
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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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Negatives of running processes with real-time priority?

The question is as the title says, are there any downsides of running processes with real-time priority (chrt -f 99)? My hypothesis is that this combined with an affinity will ensure that any ...
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Where can I see the processes running at startup?

I'm using backtrack5 R2 and sometimes when I log in the information showed says that There is 1 zombie process, where can I see what process is running?