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

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Remove Gnome Components detect by Packagename

I have tried out the dpkg, aptitude and apt commands. On the gnome desktop I decided to remove one component. sudo apt-get remove gnome-games or something else, all works fine. But if I don’t ...
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87 views

How does kill cascade in Linux? [duplicate]

Let us say I have process A which spawns process B, which spawns process C. Under what circumstances will killing A kill the whole chain (or tree I guess) and when will it not? I sometimes find it ...
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Spawning processes on a job stack

I have a hobbyist server on which I want users to upload a file, and then receive the overcome of some processing (server-side) over the given file. I am doing the processing synchronously so that for ...
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The program pstree and htop showing threads with unique PIDS. How is this possible?

I ran the program pstree -p 31872 which printed the following output: ruby(31872)─┬─{ruby}(31906) └─{ruby}(32372) The man page for pstree says: Child threads of a process ...
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143 views

How to use pgrep inside bash script correctly?

I'm running a GUI program called zeal(compiled from src) and add a script(zeal.sh) for the executable: #!/bin/bash if pgrep zeal &>/dev/null; then printf "already on\n" else ...
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How to find which processes are taking all the memory?

I'm looking for somthing like top is to CPU usage. Is there a command line argument for top that does this? Currently, my memory is so full that even 'man top' fails with out of memory :)
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How to view a specific process in top

Are there any relatively strightforward options with top to track a specific process? Ideally by identifying the process by a human readable value? e.g. chrome or java. In other words, I want to view ...
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How to determine which process is creating a file?

Given file path, how can I determine which process creates it (and/or reads/writes to it)?
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5k views

Why is SIGINT not propagated to childs process when sent to it's parent process?

Given a shell process (e.g. sh) and it's child process (e.g. cat), how to simulate the behavior of CTRL+C using the shell's process ID? This is what I've tried: Running sh and then cat: ...
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934 views

set packet rate limit via iptables

I have a packet rate limit (max. 10 per seconds) which is set by my internet provider. This is a problem if I want to use the AceStream player, because if I exceed the limit I get disconnected. How ...
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monitor a process by matching the full cmdline

I'm looking for a software that can monitor a process (specified as a partial string/regexp match (e.g. grepping) in its full command-line) in terms of cpu and memory usage. If any of those processes ...
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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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Why pidof and pgrep are behaving differently?

I have a init script in /etc/init.d/myservice for initialize a service like this: ... start() { ... daemon /usr/sbin/myservice ... } stop() { ... pgrep myservice pidof myservice ps -ef ...
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688 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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393 views

When vfork is called is parent process really suspended?

As much as I know when vfork is called child process uses the same address space as that of the parent and any changes made by the child process in parents variables are reflected onto parents ...
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Print pids and names of processes as they are created

From the question here, the OP wants to repeatedly poll the pid of a process using pidof in a shell script. Of course this is inefficient as a new process must be started for the pidof program ...
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939 views

How to find source of spawning process?

I have a Java process running on a RedHat Linux instance. The problem is it keeps reappearing after I kill it. I am not sure where to look. I've already went to crontab, but no luck. I've looked at ...
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Are there any alternatives to pidof? (smaller footprint)

Well, I've just found out that with extensive usage of pidof in very short intervals, the seemingly tiny tool can be a great CPU hog. (Source: top) On my older machine, it can easily reach 30 percent ...
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Find out what processes are writing to hard drive

On my Lenovo T400 and Ubuntu, the light for hard drive writing keeps flashing. I was wondering if in Linux it is possible to find out what processes are doing I/O to the hard drive? Just like by top, ...
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What is the meaning of every column when executing psig command?

I try to use psig command to track signal dispositions of a process on Solaris: bash-3.2# psig 3109 3109: bash HUP caught termsig_sighandler 0 ...
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Simulate an unkillable process in D state

For catastrophe testing scenarios on out server environment we're looking for an easy way to make a process stuck in D (uninterruptible sleep) state. Any easy ways? An example C sample code would be ...
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292 views

How to get whole command line from a process?

How can I get the command arguments or the whole command line from a running process using its process name? For example this process: # ps PID USER TIME COMMAND 1452 root 0:00 ...
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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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3k views

Why teamviewer starts again after being killed

My main desktop has Mint 14 and I approached it via SSH from another computer, because I didn't have a screen on the Mint one. Then I tried to start teamviewer just I order to launch its desktop ...
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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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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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Types of sleep modes for processes

I came across this while troubleshooting why our server is doing down everytime the oracle process is killed. I listed the oracle process running on the server using ps aux | grep oracle and here is ...
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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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341 views

Is there a way to see if process listening on TCP port receives a message?

According to tcpdump, my server receives the following TCP packet: 12:52:29.603233 00:19:e2:9e:df:f0 00:16:3e:6a:25:3f, ethertype IPv4 (0x0800), length 74: 10.10.10.65.38869 192.168.215.82.22: ...
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259 views

How to change the kernel max PID number? [duplicate]

The default PID max number is 32768. To get this information type: cat /proc/sys/kernel/pid_max 32768 or sysctl kernel.pid_max kernel.pid_max = 32768 Now, I want to change this number... but I ...
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59 views

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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Kill unresponsive process by name but preserve responsive processes

For some reason, I end up with a fair few Google Chrome Helper processes which stop responding, hogging CPU resources. Usually I just run killall Google\ Chrome\ Helper, however this kills all, ...
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How to trick an application to run different processes?

I am running PDFXCview.exe (for pdfxchange viewer portable version) under wine to open a pdf file, by PDFXCview.exe 1.pdf When I do the same for another file, the other file will be opened by the ...
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What determines if an executable can be run in different independent processes simultaneously?

I posted a question about how to run an executable (a PDF viewer) under wine independently in multiple processes (independent means no communication between them, it is not parallel computing). I ...
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Why do some processes pass on their cpu usage to another process when it ends?

I have wondered this for a while. For example, lets say process1 is a process that uses a lot of cpu power, like 90%. Its a video game. Then i have process2 which uses 10-12% cpu. Its a web browser. ...
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How can I see the exact command line being executed inside some bash instance?

I have a long running bash instance (inside a screen session) that is executing a complex set of commands inside a loop (with each loop doing pipes, redirects, etc). The long command line was ...
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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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Is there any UNIX variant on which a child process dies with its parent?

I have been studying the Linux kernel behaviour for quite some time now, and it's always been clear to me that: When a process dies, all its children are given back to the init process (PID 1) ...
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How to get a procesess's actual memory usage (including data in swap)

I'm trying to check how much memory strain a process is actually putting on the system, but ps, top and friends are almost useless for that purpose as they only report 3 statistics: RES - the ...
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Cron job to check if PHP script is running, if not then run

I am wondering if someone might point me in the right direction. I've got little experience working with the Linux command line and recently due to various factors in work I've been required to gain ...
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362 views

What's the purpose of the /proc/pid/mountinfo file?

What's the purpose of the /proc/pid/mountinfo file (with pid being numerical process id)? As far as I can see it reflects contents of the /proc/mounts file but with added information. Also the file ...
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838 views

Kill a process that keeps restarting

What if 'kill -9' does not work? or How to kill a script which starts new processes? doesn't help me in anyway. I have a python script which starts automatically with another process id using ...
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Strange cpu usage values reported by pidstat

I have a script that reports the cpu usage of a specific program reading values from pidstat. The script launches as: pidstat -C ^frontend$ -h -l -p ALL 1 1 The values reported this way sometimes ...
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321 views

Is reparenting from the shell possible?

This question is closely related to How to "correctly" start an application from a shell but tries to tackle a more specific problem. How can I spawn an application from a shell and thereby ...
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Terminal output from a program not opened in terminal [duplicate]

Using bash on Ubuntu, I can launch programs from command line and watch what the program is doing 'in the background' while I use the GUI frontend. This is particularly handy when a GUI progress bar ...
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Alternatives for “lsof” command?

In many cases "lsof" is not installed on the machines that with I have to work, but the "function" of lsof would be needed very much (ex. on AIX). :\ Are there any "lsof" like applications in the ...
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Using $BASHPID in grep statement

I'm trying to exclude the PID of the subshell from the results returned by pgrep. Note that the name of the file is the same as the name passed to pgrep. Why does setting a variable equal to BASHPID ...
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How can I determine what individual ulimit constraint a process has?

I have a service that sets a custom limit for open files (ulimit -n 5000) as part of its init script. My understanding is that this will be effectively for the service and its child processes. Since ...
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How can I tell when a process has finished writing to a file?

I have a process which has been spawned from a shell. It is running as a background process and exporting a DB to a CSV file in /tmp. How can I tell when the background process has completed ...
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If I use one of the exec family functions to open a child process, will pipes to parent be applied to the child?

Say I open a parent process with a master process that assigns the stdout to a file for logging. Then say I use the parent process to open a child with execvp (or any other of the exec family of ...