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

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Parent restarted by child doesn't respond to CTRL-C

I wrote a program. It starts a process (call it A) that spawns a child process (call it D) that shutdowns and restarts A. Problem is, now I can't kill A nicely from the terminal (ie. CTRL-C isn't ...
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1k 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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399 views

Does jps lie? If not, what else is this?

I am running dockerized hadoop cdh 4.6.0 with supervisor . I have opened the docker container and tried the following two commands. Got confused a lot. jps 103 -- process information unavailable ...
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118 views

how to find out the full path of the command from the result of lsof -i

lsof is a great utility, just now started using it. lsof -i | grep smtp => this give the following result. httpd.pl 212548 global 3u IPv4 893092369 0t0 TCP ...
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59 views

Is it possible to make an exec call that “returns”?

Is there a way to make the exec system call work like a function call that returns instead of totally replacing the current process image? My motivation is trying to integrate two shells with ...
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71 views

Disable networking only inside of a single terminal

I want to run a command in the terminal to disable networking, just in that terminal. How can that be accomplished? I'm running OSX. Note: I only want to disable the networking in that terminal. ...
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194 views

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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205 views

How do I execute in background / return early?

For reference, I'm using phpseclib to control a remote SSH server using the 'root' account. I have to start/stop a java process which is ran in the background. Stopping works fine with killall java ...
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107 views

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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177 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 ...
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30 views

Identify process

Every couple of minutes my Mac OSX machine starts running a process that consumes 10% of the CPU. It runs for a couple of seconds and then stops. I can see the process coming up in 'Top', but the name ...
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82 views

“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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48 views

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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61 views

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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143 views

API Monitoring and Hooking

I am currently reading the "Malware Analyst's Cookbook and DVD". There is a chapter "Dynamic Analysis" and there are also some recipes about hooking and monitoring API calls of process but it is for ...
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56 views

Why are the process priorities not respected?

I was running four jobs in the background with HTCondor. It sets the priority to 10. Then I was compiling something with make -j4 in the foreground (priority 0). However, the HTCondor jobs still got ...
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80 views

Cgroups - memory subsystem

I want to set the memory.limit_in_bytes parameter for a control group and disable OOM, so processes freeze when the limit is reached. But i want to change that limit dynamically, if there is more ...
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91 views

CGroup Processes Not Terminated even when main process has been killed through Systemctl stop command

I am running systemctl stop process command for some process. Please find the output for systemctl status process below: Loaded: loaded Active: deactivating (stop-sigterm) CGroup: ...
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85 views

Getting non-stored password from Icedove

I've recently changed my mail password (because of Heartbleed), but I've forgotten the new one. When entering the new password in Icedove, I didn't think of clicking "remember password", but the ...
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389 views

how to stop kernel threads preempting real time user space processes?

I created some processes in user space and tried to visualize its working in kernelshark with the trace recorded using trace-cmd. But kernel processes like the ones shown below are preempting my ...
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138 views

How to find current chroot jail path on Linux <2.6.26

While running kernel 2.6.26 or newer it's possible to get the path of the current chroot jail by comparing the mountinfo of the current process and the init process. Is there a way to get the same ...
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27 views

If processes can't modify their parent's environment, what is MC doing?

As far as I know, a process cannot modify its parent's environment. However, when I run mc (GNU's Midnight Commander, a curses-based file manager) and then quit it, I end up with another $PWD: ...
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24 views

Is there any considerations I should take when running untrusted apps as non-root user?

I have to use an application I don't trust (unstable) and I will run it as a non-privileged user so if something bad happens the damage would be limited to the home folder of that user. I removed ...
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38 views

Create tree of processes

I'm implementing pstree as an assignment, and I would like to create test tree of processes, but I'm struggling to do so. I tried to do something like this to create tree of background processes ...
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57 views

process blocked in msgrcv

I have a process that is blocked in msgrcv as shown by ps -eo pid,tid,wchan. Is there any way to find the PID of the process that my process is expecting to receive a message from? The communication ...
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18 views

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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104 views

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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133 views

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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94 views

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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39 views

What does the “k” metric mean in the “sa” output?

From man sa: k cpu-time averaged core usage, in 1k units My questions: How is it calculated? What is the significance?
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22 views

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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74 views

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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165 views

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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199 views

Measuring context switches of a LWP gives incorrect results. Why?

I have a Java thread pinned at my cpu core. It is busy spinning and I see through top that it is running fine: %Cpu0 : 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu1 : ...
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173 views

Why is the service unavailable the second time?

How can this happen? /volume1/homes/me $ tdtool --list /volume1/homes/me $ tdtool -e 44 Learning device: 44 - Could not connect to the Telldus Service /volume1/homes/me $ tdtool --list Error fetching ...
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169 views

How to send a running process to jail?

"Go directly to jail; do not pass go, do not collect $200" — Monopoly Is there any way to make a running process's all future file access behave as if it has always been in a chroot environment?
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373 views

gnome-terminal cmd leaving processes open after closing parent window

The following simple command should demonstrate my issue: gnome-terminal --tab -t "Tab 1" -e "/bin/bash" --tab -t "Tab 2" -e "/bin/bash" This should open a new window with two tabs and an active ...
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203 views

Rogue Java process brings my computer to a halt

In reference to my earlier post: Is there a log of past threads that are now closed? I gave the process a kill -STOP signal and started examining the details. I can't seem to figure out why it is ...
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6 views

Page Fault Frequency Algorithm - Compute number of frames and mean resident set

I'm reading about Page Fault Frequency algorithm but I don't understand how can I compute the number of frames. For example I have my reference string: 112233444412412214432255543 and control ...
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134 views

Why does my redhat 5.11 system have so many ext4-dio-unwrit processes?

I have a redhat 5.11 system running, and it looks like there are 32 of these processes. What are they, and why are there so many of them?
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66 views

how to find out why process is taking more cpu usage

Sometimes load goes high on server for java processes. Multiple java processes are running and consuming high load on server. I want to know how to check that why process is taking too much load.
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22 views

Perform task on waking up from suspend

I have program that misbehaves when my pc wakes up from suspend to ram, it starts using up to 40% of processor time so i usually have to kill it manually. How can i set specific command (pkill in ...
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64 views

Send a remote job to a remote server (second machine) and end the first process

I Installed ScanBD for my scanner on a RaspberryPi. I also wrote a script to process the files once the scanning function has completed. SCANBD Script SCANBD Process Script Currently, the scans are ...
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80 views

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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40 views

Why are some processes “killable” by pkill but not killall?

I had over 20 instances of httpd (apache) processes running, so I decided to shutdown these. Normally I use killall, But when I typed killall httpd it just said: No matching processes belonging to ...
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315 views

System CPU Time and User CPU Time Calculation for a Process in Linux

I want to calculate CPU time consumption of a particular process in system mode and user mode using statistics present in /proc/<PID>. There are two fields utime and stime in ...
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How to start Process state

Over and over and also aver again. I saw this picture on operation system text book. But this time, I want to see the codes to understand this picture more tangible. where is codes which their duty ...
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24 views

How do you adjust other user's job priority?

Let's say your coworker started a very intense process and went home. It's occupying most of the CPU resources, and you can't do your stuffs because of it. If it was your own process, you could run ...
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427 views

Tracing system call on Ubuntu 12.04

The main task I have to carry out, is to trace the system call of processes in ubuntu 12.04 LTS. Problem is, I am unable to trace them continuously, i.e. as soon as they are added to the system, they ...
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42 views

Is it possible that a method inside a module (in kernel mode) be preempted?

My basic question is about system stack of a thread, and system stack of a process Two methods in a module? Which of the methods can be preempted via kernel mode preemption, the one in process ...