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

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Linux ps -elf command output, what is Process Flag meaning?

In output of ps -elf command in linux, we can recognize that process flag of 4 and 1, and process flag of 5, (sum of 1 and 4), but what is meaning of process flag 0 ? unfortunately, man does not help ...
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22 views

Open ports with no associated PIDs

I have some open ports on my laptop but netstat is not reporting which PID/Program is associated with them: $ netstat -tulpn (Not all processes could be identified, non-owned process info will not ...
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2answers
2k views

how to find out namespace of a particular process?

I already asked a question about how to list all namespaces in Linux, but there wasn't any correct and exact answers, so I want to find out a method which can help me to find out the namespace of PID ...
6
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1answer
57 views

Is it possible to add a process to the job list in bash (e.g. to reverse “disown”)?

If I disown a job in bash and change my mind, can I undo it somehow ? If so, taking it further, is it possible to bring an arbitrary process under job control (an acceptable restriction would be that ...
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0answers
274 views

Monitor if a process has terminated in C [migrated]

Introduction I am writing a monitoring program in C, which performs the fork() and exec() cycle. However I need to check whether the child process has terminated or not without blocking the main ...
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2answers
28 views

Directory in /proc that isn't process dir but start with number?

Quick question. Is it possible to create directory in /proc that starts with number but isn't process directory (where name is PID)? I write software that searches for process directories and I wonder ...
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3answers
1k views
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2answers
176 views

What does p and e denote in exec family of calls?

l and v in exec calls denote whether the arguments are provided via list or array(vector). I read it somewhere that p denotes the user's path and e denote the environment but did not understand what ...
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1answer
27 views

Restricting CPU time of processes by executable path

Is there a way to restrict CPU time (duration) for all processes which are invoked by executables that are located in a certain directory? I would like to be able to auto-kill all applications which ...
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3answers
36 views

What does it mean to run a process in background? [duplicate]

What exactly does it mean to run a process in the background? The difference between $program and $program&: Is it just that the input file descriptor is not inherited from the shell or is there ...
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2answers
139 views

Zombies in bash

Bash doesn't seem to create zombies. It looks like the processes get immediately reaped when they get killed. Can I make bash make zombies? Why I'm asking: I'd like to be able to safely kill a ...
3
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2answers
42 views

foolproof way to detect if java process is running

I have a java process that runs continually that sometimes, for reasons I have yet to fully debug, craps out. So, I also have a cron job that looks for the process every 5 minutes and if it finds the ...
2
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1answer
27 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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1answer
33 views

Resource (CPU time and memory) limitation and termination of a process upon violation in Linux

The problem: Given a process, limit the resources it and its child-processes can use. I.e. set CPU time and virtual memory quotas. When the process group exceeds one of the limits, terminate it, ...
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5answers
76k views

How to check how long a process has been running?

I would like to avoid doing this by launching the process from a monitoring app.
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4answers
6k views

nohup vs. Screen

In the past, I've used nohup to run big background jobs, but I've noticed that a lot of people use Screen in this context. Does Screen provide some kind of functional advantage that I am unaware of, ...
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1answer
41 views

What is the actual process name when nautilus is copying files?

I am copying some files from an external drive to my desktop running Ubuntu. I can see the "File Operations" dialog which shows copying process. How do I find this particular process in ps aux | grep ...
2
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1answer
27 views

How can I know threads names that run on specific core

I am working in java code,my code attend in making specific java thread run on specific core and in this code i give names for java threads.I need linux command that enable me to know threads names ...
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2answers
1k views

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 ...
3
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1answer
32 views

Why can the waitpid system call only be used with child processes?

The man page wait(2) states that the waitpid system call returns the ECHILD error if the specified process is not a child of the calling process. Why is this? Would waiting on a non-child process ...
2
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1answer
41 views

How to kill a task that cannot be killed (uninterruptable?)

I have a task running that blocks pm-hibernate (on Linux 4.0.7-2). When I try pm-hibernate there is an error message "Freezing of tasks failed after 20.002 seconds (1 tasks refusing to freeze, ...
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2answers
22 views

bash + how to hold shell scripts

Is it possible to hold/stop the bash script progress without to kill the process? ( by kill command ) or other command For example this script - install_linux_pkgs.bash , will install Linux pkgs ...
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3answers
721 views

Check that fail2ban is running?

I just installed and configured fail2ban. I want to make sure it is working. I don't want to block myself from the server so I can't just login (poorly) a bunch of times. How do I see that fail2ban is ...
2
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2answers
45 views

How do I kill a process after detaching it from bash?

I have multiple scripts that detach a process from bash using nohup and &>/dev/null &. My question is, how do I kill the process after completely detaching it from bash. using killall or ...
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1answer
62 views

Why does my process take too long to die?

Basically I'm using Linux 2.6.34 on PowerPC (Freescale e500mc). I have a process (a kind of Virtual Machine that was developed in-house) that uses about 2.25 G of mlocked VM. When I kill it, I notice ...
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1answer
50 views

Process command

When I used ps -u root command in Ubuntu it showed the following output? PID TTY TIME CMD 1 ? 00:00:02 init 2 ? 00:00:00 kthreadd 3 ? 00:00:00 ksoftirqd/0 5 ? ...
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1answer
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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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Find which process is being joined by another?

If I have open Nautilus and spawn a new Nautilus instance a new PID is created for the new Nautilus instance. Shortly after, the instance is being joined with the main Nautilus program running. Main ...
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1answer
711 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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1answer
45 views

Is there a robust way for a child process to signal readyness to its parent? [closed]

I have a (Java) process which is staring a separate process foo. foo takes some number of seconds to start up, then is really running. Control returns back to the parent process as soon as foo is ...
2
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1answer
61 views

list processes belonging to a network namespace

I am on Ubuntu 12.04, and the ip utility does not have ip netns identify <pid> option, I tried installing new iproute, but still, the option identify doesn't seem to be working!. If I were to ...
21
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1answer
539 views

What does it mean to have a minus sign as the first character of a command in htop output?

In htop, or other commands that show process status, all bash processes have in the command column /bin/bash but one process has in the command column -bash What does it mean?
9
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1answer
914 views

Still alive, still alive after kill -9 / SIGKILL [duplicate]

An apache2 process got stuck on my server and caused problems with other services. (original problem: kerneloops after USB hardware disconnect) root@server:~# ps aux | grep apache2 | grep -v grep ...
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Inconsistent output on /proc. Can some processes be hidden? [duplicate]

When I list /proc/<PID>, works as expected. But when I use ps or ls /proc | grep <PID>, the process is hidden. How & Why is this possible? [user@host ~]$ ls /proc/12263 attr ...
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1answer
80 views

Is it possible to know the source (application) of the clipboard?

I've noticed that sometimes clipboard contents become unavailable if the source application (where the content was copied from) is closed. This leads me to wonder if it's possible to know what the ...
2
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1answer
72 views

Process startup after boot

I know the following are ways processes get started in Linux from init.d (or similar) from shell (by user) forked by a running native daemon Is is ever possible on Linux for a process to be ...
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2answers
57 views

Why is the range of load average not 0-1+ for all cpu's together?

I know that load average is 0-1(or 0-1024) per cpu. E.g a busy quad-core can have a load average of 4.0 or higher. (e.g if there are many tasks). I understand it can be huge like 100+ etc. I also ...
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7answers
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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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1answer
33 views

How can I find out which mounted filesystems a running process sees?

After having a long debug session and finally finding out that in Fedora (and CentOS) php-fpm has its own mounted /tmp filesystem, which was caused by a systemd setting, PrivateTmp, I am wondering if ...
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0answers
15 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 ...
0
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1answer
31 views

Kernel current working directory and inode information placement

I'm reading some doc about UNIX but I don't understand two things: Why is important for the kernel to know the current working directory of the running process? Why not keeping the inode information ...
2
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6answers
373 views

How to close all proceses without restarting a machine?

I have a lot of processes running and I need to kill them all. How can I do this without restarting a machine?
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4answers
3k views

chdir(<directory>) doesn't change directory after exiting to shell

I wanted to make a simple C program to change to my project directory. Its content is as follows: #include <unistd.h> int main() { chdir("/home/enedil/projects/algo"); return 0; } I ...
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1answer
26 views

Stopping jobs by PID?

Could someone tell me why I am unable to kill the jobs below when specifying their PID? I can stop the jobs when using their % id. Mac:~ gd$ ps PID TTY TIME CMD 4523 ttys000 0:00.02 ...
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1answer
43 views

Sending signals to long-running processes (AWK, DD)

I'm familiar that DD command doesn't produce output while running. However, if I send a USR1 signal to it, it can print current state. Can I do the same with AWK? Prints its variables, register ...
3
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2answers
54 views

Sum the memory usages of all the processes of a program?

How can we sum the memory usages of all the processes of a program? For example, I have opened many Chrome tabs for webpages, and each tab runs a different process. How can I get the total sum of ...
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1answer
28 views

Show CPU core usage for parent process and its child processes

Is it possible to display CPU core usage just for a single process and its child processes on Linux?
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340 views

How to locate a Chrome tab from its process PID?

I opened many Chrome tabs for webpages. Each tab has its own PID, e.g. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND t 3900 1.9 6.3 5718440 508660 ? Sl ...
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2answers
93 views

What to do when “nice” isn't good enough (FreeBSD)

I've been using x265 to encode some video on my workstation lately, but I have a problem: even though I launch it using nice -n 20 x265 to deprioritize it, it still slows the computer to a crawl while ...
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1answer
26 views

How to guard a set of folders from being written into by a specific process?

I would like to have a way in which a set of folders do not allow write access for a particular process. For example, I would love to have a way in which YUM/RPM is not allowed to write into /usr/bin ...