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

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What is the most Unix-y way to handle stdout for a backup command that might fail?

I am writing a utility/script (in Python, as it happens) to run on Linux, which backs up data from a remote server, and outputs to stdout. At the moment, I run this script on the hour from cron, and ...
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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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2answers
25 views

Can you make a process pool with shell scripts?

Say I have a great number of jobs (dozens or hundreds) that need doing, but they're CPU intensive and only a few can be run at once. Is there an easy way to run X jobs at once and start a new one ...
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Stop all processes by a user: children of supervisord are still running

I'm trying to delete a user but it keeps saying that user is currently used by process ID x I tried everything here and here, nothing works, how do I kill all the process by a certain user in order ...
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How do kernel inform OSPF daemon when a physical interface status is down?

When a physical interface status is changed from up to down, there are 3 things related to the computer's current routing table and OSPF. The (connected) network for that interface and remote ...
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Why file-nr and lsof count on open files differs?

I am running into a problem all of a sudden; all my applications and the server was running fine and all of a sudden I see the number of open files shoot up. I am checking it with this command: cat ...
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788 views

How to get start time for a defunct process on AIX?

When I run the following commands on AIX: 22:root@SERVER:/root # ps -ef | head -1 UID PID PPID C STIME TTY TIME CMD 22:root@SERVER:/root # ps -ef | grep defunct | head -1 ...
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What does “task mysqld:xxx blocked for more than 120 seconds” mean?

We are troubleshooting a MySQL issue where some queries are taking a very long time complete and I see many of these entry in /var/log/messages: Jan 28 05:52:15 64455-alpha01 kernel: [2529273.616327] ...
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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, ...
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20 views

Get total bytes sent by pid

I have some processes in my unix system that sends data to a remote machine. It is possible to fetch the total bytes sent per pid ? In general, how i can monitor that pid in terms of network? Thank ...
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Is there a way to change the number of processors a program sees?

Is there any way I can trick a program into thinking the system has fewer processors? To explain: I am debugging a program that creates as many threads as it has processors, using ...
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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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How can I check what signals a process is listening to?

How can I verify whether a running process will catch a signal, or ignore it, or block it? Ideally I'd like to see a list of signals, or at least not have to actually send the signal to check.
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2answers
689 views

How to compute Linux slab memory leak in GNU/Linux ( proc/slabinfo ) of running process

How to compute Linux slab memory leak in GNU/Linux ( proc/slabinfo ) of running process ? I'm want to free usage is not working properly . I want to way how to check Memory Usage & Memory Leak ...
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2answers
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ls -l /proc/self | increamental PID?

Each time, when the commandls -l /proc/self is executed, the link points to process who's PID keeps increasing. Why is this so ? Is it the PID of the ls command ?
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Serial port locked by random process

I have an issue with trying to open a USB device's serial port with pyserial. It seems that as fast as I connect the device, /dev/ttyACM0 is used by some random process. ModemMana 851 root 8u ...
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6answers
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How can I close a terminal without killing the command running in it?

Sometimes I want to start a process and forget about it. If I start it from the command line, like this: redshift I can't close the terminal, or it will kill the process. Can I run a command in ...
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2answers
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start process (as root) upon user login

I would like to start a process as root upon each user login. The motivation beside this is, that the process will work on encrypted home folder of particular user folder. How can I achieve this?
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1answer
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How to do a netstat that will only filter based on pid

How can I have the following command below just show/filter based on the PID's I'm looking for? sudo netstat -lp --inet The results come back as this Proto Recv-Q Send-Q Local Address ...
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How do Linux PIDS increment

Why do PIDS under Linux (generally) increment by 4? The only exception I can think of is startup processes run by systemd, which increment by 1 when they are related or 2 otherwise. How was the ...
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“Restart” a process in the same terminal?

I put "restart" in quotes because the following question on SO illustrates what I'm trying to do: http://stackoverflow.com/questions/27957091/restarting-a-process-in-the-same-linux-terminal I'm ...
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1answer
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I can't install new packages and can't update and upgrade

I'm trying to install some program on Ubuntu, but when I try it I got the following error.- E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock ...
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do processes access cpu and memory by system calls to the kernel?

If I am correct, processes access devices by system calls to the kernel. CPU and memory are also devices. when a process starts to run, does it get cpu and memory by system calls to the kernel? ...
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396 views

How can I kill child processes with start-stop-daemon?

I'm writing a simple web server using nc and bash. It looks like this: #!/bin/bash rm -f /var/run/streamman/out mkfifo /var/run/streamman/out trap "rm -f /var/run/streamman/out" EXIT while true do ...
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How can I disown a running process and associate it to a new screen shell?

I have a running program on a SSH shell. I want to pause it and be able to unpause its execution when I come back. One way I thought of doing that was to transfer its ownership to a screen shell, ...
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Count the total number of sub-processes (recursively) spawned by a command

How do find the total number of child processes (recursively) spawned by a script? For profiling purposes, it is sometimes important to count the generated sub-processes of command, script, etc. ...
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When was a process started

To know when was a process started, my first guess was to check the time when /proc/<pid>/cmdline was written/modified the last time. ps also shows a START field. I thought both of these ...
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Monitor the creation of new processes

I want to get a notification whenever a new process is created. I've tried to use inotify on /proc, but it didn't report any event even though a new directory appeared in /proc. I could list the ...
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Using aircrack-ng for Fedora 20

I installed aircrack-ng from my repository. Is it strictly command line only? How do I start/enable aircrack? What are some basic commands a/o syntax?
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1answer
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Why cannot we kill a zombie? [duplicate]

I am editing this question since it was marked duplicate as another question about how to kill a zombie process. I am not looking for an answer to how to kill a zombie process. I do not have zombies ...
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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?
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What is the difference in CPU utilization between 'ps aux' and 'ps -ef'?

I use Ubuntu 12.04.1 Linux. I see a difference between %CPU and C output format of ps command for a process. It is not clearly noted in the ps man page. Man pages says: CODE HEADER ...
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What uses Linux “application memory”?

Just for fun, I wanted to watch what ls -lR / does to my "buffers" memory on a Linux system. As expected, the value increased. But I noticed that the "application memory" (i.e. "used" - (buffers + ...
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grep invading my ps [duplicate]

When I'm checking for some process, I usually write ps aux | grep myprocess And sometimes I get the output of eimantas 11998 0.0 0.0 8816 740 pts/0 S+ 07:45 0:00 grep myprocess if ...
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1answer
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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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1answer
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What is kondemand?

I have searched the web for the answer of this question but couldn't find a clear answer. Best answer I found was as follows: kondemand is a kernel thread that belongs to the ondemand governor of ...
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1answer
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“incrond dead but subsys locked” what does it mean?

While running "service incrond status" it shows "incrond dead but subsys locked". Can you please tell me what does it means. Normally its status should be running. Let me know what may cause it to ...
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363 views

Very large values for utime and stime for foo. Is foo still running?

I am running a program foo It has been running for close to 30 days now (even more) Until around 10 days ago (I cannot be very exact) it used 100% of one cpu on my dual core laptop (it was at the ...
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1answer
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fork() and how signals are delivered to processes

I program that I wrote in C fork()'s off a child process. Neither process will terminate. If I launch the program from the command line and press control-c which process(es) will receive the interrupt ...
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Determine the owner of the session of a process

I am trying to implement a way to determine which user is owner of some process's session, in a way that's as cross-platform as possible. In Linux I can trace the process's pty by following the link ...
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1answer
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Equivalent command for ``time`` for memory usage?

by using time we can easily get the information about how long a program run, I was wondering if there is any equivalent command I can use for memory usages? Like how many memory are allocated for ...
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1answer
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Bash update list of running jobs with ps

I need to run in parallel a set of computationally intensive tasks. What I was trying to do is to maintain a list of pids corresponding to the running jobs and update the list of running jobs with ps ...
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5answers
570 views

How to kill stubborn process

I've an annoying process that won't die: ps -A | grep "nzbget" gives me: 11394 pts/3 00:00:00 nzbget If I try: pkill nzbget (or 11394) ...I get no response and the process is still alive, ...
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Process history in Unix/Linux systems

I know that ps -efl shows running processes on *nix systems. I would like to check history of the (past) processes that have been run on a particular machine, preferably with all the information ps ...
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2answers
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A process is a program that is loaded into RAM [closed]

Is this correct? Basically, programs are simply code on hard disk and they are called process(es) when they are in the RAM, right?
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Can Process id and session id of a daemon differ?

As far as I understood from different articles and here , a daemon has the following features: Parent Process ID should be 1. No terminal should be associated with the process. The process id, ...
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How to stop a background process?

I have started a wget on remote machine in background using &. Suddenly it stops downloading. I want to stop its process, then start it again. How can I stop it? I haven't close its shell window. ...
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'htop' process and threads cpu usage?

I'm observing a multi threaded process in htop in tree view. If I were to strip it just to the problematic part, it looks somewhat like this: CPU% bin/process 100 `- ...
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pkill -P $ID working while kill — -$ID not

I was playing around with creating and killing process groups on linux ( ubuntu ) I am trying to kill a process group and am being driven crazy by the fact that pkill -P $ID works while kill -- -$ID ...
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Process id of a command ran by an user

Consider i am running just some basic command.. ls Now would the above command have a pid, when it was getting executed? If yes, then how can i determine that pid? when i try echo $! right ...