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

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Why is `sudo pkill -HUP -f “nginx: master process”` returning code 129 and no output

I'm trying to trigger a reload of the Nginx master process by using pkill and sudo. The server reloads fine, but I was just curious if anyone knows why the command sudo pkill -HUP -f "nginx: master ...
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Find processes using a network interface

I'm trying to find a way to safely shutdown a network interface, i.e. without disturbing any processes. For this I need to find out what processes are currently using that interface. Tools like ss, ...
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172 views

How to constrain the resources an application can use on a linux web server

This is the situation: I have a PHP/MySQL web application that does some PDF processing and thumbnail creation. This is done by using some 3rd party command line software on the server. Both kinds of ...
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560 views

Prevent users from killing processes that they own

I have started some processes (window based) from user's .bashrc file. I want to prevent users from killing those processes. Is there a way to transfer the process to superuser so that a normal user ...
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How to know maximum memory usage of a process? [duplicate]

Possible Duplicate: Measuring RAM usage of a program I have a process, which is quite short-running (about 10 minutes), but memory heavy. I want to know how much memory does the process ...
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1answer
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How do I detach a process from its parent? [duplicate]

Possible Duplicate: How can I disown a running process and associate it to a new screen shell? The problem is that the process is not a job inside of my active shell (as I've logged in from ...
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1answer
920 views

What process created this window with no PID associated? [duplicate]

Possible Duplicate: What process created this X11 window? I need to kill a process that spawned a window which seems to have no PID associated with it. At least that is what xdotool says: ...
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165 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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589 views

How to log processes in daemon-mode?

I would like to save the standard output of the program motion in a text file. If I don't use motion in daemon-mode I would simply do it by: motion > log.txt But what is the equivalent when I ...
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mmap() failed: Cannot allocate memory - how do I find out who's complaining?

mmap() failed is popping up in my .xsession-errors in bursts. But there's no indication about what application it is failing with. How do I look into this after it has happened? I usually discover the ...
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185 views

How to detect out-bound port from PID

I have several applications that run on random ports. How would I take the pid or the file location and find which port it is running on? Example of desired output: www-data/apache = 80 ...
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Write inside a socket open by another process in Linux

Is it possible on Linux for a process to write inside a socket open by another one? Let's say I open a connection to google.com using netcat: myuser@linux:~$ nc google.com 80 Now I can lookup for ...
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337 views

How do I see more of the command line with the KDE System Guard Process Table

I often have several java programs running and I can't tell which one needs to be killed. The command section of the process table only shows java, but doesn't tell me which jar or class files it is ...
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Hide processes from other users based on groups (under Linux)?

Is it possible to configure process hiding for certain user groups under a linux system? For example: Users from group X should not see processes owned by users from group Y in ps/top or under /proc. ...
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Save entire process for continuation after reboot

I developed an algorithm for a fairly hard problem in mathematics which is likely to need several months to finish. As I have limited resources only, I started this on my Ubuntu 12.04 (x86) laptop. ...
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1answer
413 views

Giving input to background processes

Is there any way to give input to background processes or which run as daemon processes? I was coding some Puppet configuration files and I had to push them to some remote machine. For that purpose I ...
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3k views

Difference between poll_s and ep_poll WCHAN in ps output

When I issue ps -elf|grep python for example on my system, I see these: 1 S 1000 6020 6008 0 80 0 - 9914 poll_s Jul12 ? 00:00:01 python manage.py run_gunicorn -t 3600 -w 8 -b ...
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What are “session leaders” in `ps`?

What are session leaders, as in ps -d which selects all processes except session leaders?
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215 views

Set a callback for when a certain process is spawned

The script I'm writing launches process A, which after an uncertain amount of time, launches a child process B. I need the script to execute a command C which depends on process B. But B might not be ...
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Linux running slow with 0 swap left

Our Linux server is responding very slowly. top doesn't show any excessive CPU usage. I noticed that even though there's about 5GB of free memory, the system is using all of swap with no free swap ...
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874 views

When you try to terminate a process for good, which option for “kill” should you use?

I am getting a lot of mixed messages from people, and was wondering if it there really is not much of a difference in what you use. kill 'x' killall 'x' kill -9 'x' These are some options I've been ...
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1answer
717 views

Rationale for making user space text segment start at 0x8048000

I read somewhere that (at least since Linux v. 2.6) all user-space code is placed at load address 0x8048000 in the virtual memory address space. My own observations confirm this. I have done a cat ...
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How can I kill the top CPU/IO process quickly?

I find that sometimes my Linux will stop responding, so I need to switch to another terminal with CtrlAltF2, and type a command to kill the top CPU usage process or top IO usage process, so that the ...
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227 views

How can I log what software I use the most?

I really like using open source software and would like to help fund further development. Unfortunately, I have limited funds to do so. Being somewhat greedy, I would like to donate to the projects I ...
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166 views

Detecting whether a server is loaded

I have to start some performance test on a Rhel 6 box, but before starting the test, i have to make sure there are no other java processes running. The manual way of doing it would be to use "ps -ef ...
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339 views

Quick and dirty way to run a process more than once

I am looking for very simple bash script that would allow me to launch a process a few times. What's essential to me is that after the processes terminate, everything will clean up automatically. ...
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In bash, what are potential negative consequences of pausing a process with control-z?

Using bash, one can pause a process with control-z. However, are there any general circumstances or guidelines to beware of where a process would not behave well with being paused? My specific ...
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Kill all processes related to an application

I have two processes that are temporarily spawned and I need to kill them. Here are the processes from ps aux david 38329 0.0 5.0 3916476 104624 s002 S 11:33AM 0:17.43 ...
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How to pass data outside process for zenity progress?

Usually this would be a question about how to pass data from a subprocess to a main process, but maybe zenity has some extra quirks so please focus on zenity. Example: #!/bin/sh ( echo "10" ; sleep ...
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Launch independent process [duplicate]

Possible Duplicate: How can I close a terminal without killing the command running in it? If I open a terminal emulator, type firefox & and then close the terminal, the process it ...
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1answer
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The TIME field in ps -ef

When I do ps -ef, I see "TIME" field. What does this field mean? From what I understand, this tells the actual CPU time, that the process got (amidst all the context switching). Does the TIME field ...
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1answer
144 views

Is there a way to determine which process creates a file on osx 10.6.8

I would like to know which process has created files on os X 10.6. I'm trying DTrace, which probably will give the right answer, but I have not eyes to see the method. I'm doing this because I think ...
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How to preload my .so everytime an application executes?

I've successfully used a hook under linux with this article: http://hackerboss.com/overriding-system-functions-for-fun-and-profit/ Now I want to make my .so file load every time espeak loads up. No ...
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Set process exclusivity in Linux

I am trying to measure the performance of a process. I have widely ranging performance measurements on small bit of single-threaded deterministic code that should perform the same every time. I would ...
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How to reload a background process?

I have a python script which I would like to run in the background. So I do this: $ nohup python script.py & If I am frequently making changes to the script, I need to terminate the process ...
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why new pid is smaller than the old ones?

Is there any chance the new process's pid is smaller than the existed ones ? I have a daemon process which will restart when be killed, I recorded the pids, and found that the pid first came smaller, ...
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How do I get a mapping of Pid to Port?

I have a process which I need to run on a specific port. I have started some other process on that port and I need to kill it. Unfortunately, I don't remember the name/pid of the other process so I ...
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Need help with understanding output of ps -ef on linux

When I do ps -ef on my Linux box, I get: UID PID PPID C STIME TTY TIME CMD Please help me with meaning of C,TIME. is the TIME , the actual cpu time allocated to the process?
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How do you prevent user from opening a program?

I'm trying to write a script which prevents the concerned user from opening programs (mostly internet browsers) from being run during a certain time (like 1000 to 1200 hrs). This is like a ...
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1answer
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Apache cannot fork: cannot allocate memory

I am running apache on Fedora with mod_perl. The server forks a process to send an email frequently - and the fork exits. Suddenly, I got: Cannot fork: Cannot allocate memory. There was plenty of ...
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Why is there a type for process ids (pid_t), but not for file descriptors (fd)?

I see that pid_t is typedef'd in unistd.h, and file descriptors are defined to be int in fcntl.h. But since they are used in similar ways, wouldn't it make sense to have a typedef for file ...
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Need explanation on Resident Set Size/Virtual Size

I found that pidstat would be a good tool to monitor processes. I want to calculate the average memory usage of a particular process. Here is an example output: 02:34:36 PM PID minflt/s ...
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153 views

Get process list with logical intersection of selectors?

The Linux ps command allows multiple selectors, such as user and command name, but always returns the logical OR of those selectors (more than I want). Does anyone know of a method or tool already ...
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541 views

Process Migration Scripting

I want to write some shell script which can perform the process migration from one node to another. Is it possible ? Can somebody please help me scripting this. What all should I know before coding ...
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Preventing program from using internet

Is there a way to block certain programs from being able to connect to the internet in Debian (a firewall blocking outgoing connections), so for example, to block a windows program running in wine ...
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1answer
497 views

Redirecting/grep'ing an existing shell's STDOUT

I run a lot of long running processes (simulations) that print progress to STDOUT. I occasionally forget to redirect to STDOUT to a file I can grep, and it's usually too far along to restart. ...
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632 views

Force change of a user's cwd as root

I'm looking to change a user's process such that I can set it's cwd. Related, and secondary to the question, I have a filesystem I want to unmount but a user is sitting on it with a bash process. I ...
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How often is PSS value updated for a given process in /proc/pid/smaps

So if n processes are sharing a library L with size M then the contribution to their PSS is M/n. Now imagine one of the process terminates. So the contribution would be M/(n-1). Q1: My question is ...
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How is /proc/self implemented in Linux?

I was tinkering around with the /proc filesystem in Linux, and I came across /proc/self, which is a symbolic link to the process directory of the current process. I would like to know how it is ...