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

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What is the difference between running a executable just by name and by appending a dot /slash before it?

This is the output from ls -all command : -rwxr----- 1 subhrcho dba 3600 Nov 13 17:26 jdev -rw-r----- 1 subhrcho dba 1566 Nov 13 17:26 jdev-Darwin.conf -rw-r----- 1 subhrcho dba 347 Mar 6 2009 ...
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721 views

Harddrive I/O per Pid

is there any way to see the disk I/O per pid/process ? Monitorix shows me the following and correct me if I´m wrong, but it looks like that the harddrive is slowing down the whole system: UPDATE #1 ...
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Terminating a bash shell script running in the background

I often use bash shell scripts to run simple commands for many different files. For example, suppose that I have the following bash shell script, called script.sh, that runs the program/command foo ...
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1answer
614 views

will the same pid be used after getting killed?

I had a file opened using vim editor. It was in a ssh session and since I had been idle for a long time, the session got closed and I had to establish the connection again. I opened the file again ...
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3answers
498 views

Dynamic file content generation: Satisfying a 'file open' by a 'process execution'

I have a read-only file, F. A program, P, that I'm not the author of, needs to read F. I want the content of F to come from another 'generator' program, G, whenever P tries to read F (taking F to ...
5
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1answer
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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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1answer
239 views

Why is the following command killing a system?

Anyone understand the following code , running in bash ? :(){ :|:& };: It seems to be a "fork" bomb on Linux.
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Real time processes scheduling in Linux

I have been learning some scheduling concepts. Currently my understanding so far is as below. There are real time processes and non real time processes. Non real time processes can have nice values ...
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268 views

LD_PRELOAD or similar to prevent network access

I'd like to start a program disconnected from the network (because immediately upon starting it tries to download huge amounts of data, which can be prevented by changing settings as soon as it ...
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2answers
1k 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 ...
2
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1answer
93 views

Find out to which directory a process is writing?

This question is NOT a duplicate of this question Find out current working directory of a running process?, because the writing directory can be different from the working directory. For example, I ...
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What is the difference between ps and top command?

What is the difference between ps and top command ? I see that both can display information about running processes . Which one should be used when ?
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Elegantly get list of descendant processes

I would like to get a list of all the processes that descend (e.g. children, grand-children, etc) from $pid. This is the simplest way I've come up with: pstree -p $pid | tr "\n" " " |sed "s/[^0-9]/ ...
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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 ...
6
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2answers
598 views

How can I allow a user to prioritize a process to negative niceness?

I want a user to run a specific process on the system with a negative nice value. I can't simply fork the process to background as this specific program is a minecraft server and I rely on the command ...
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3answers
410 views

How can you change the process name of Wing IDE from python to something more descriptive

In my process list under Ubuntu (using top/System Monitor) one of the largest memory hogs (200+Mb) was python. I searched a bit for one of my programs to be the cause until I realised this was my ...
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Bash script wait for processes and get return code

I am trying to create a script which will start many background command. For each background command I need to get the return code. I have been trying the following script : #!/bin/bash set -x ...
5
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1answer
6k views

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
1k views

Maximum memory usable by a 32 bit RHEL 6 system

I have installed a 32 bit RHEL OS on a 64 bit system. From the wiki page of PAE: The Linux kernel includes full PAE mode support starting with version 2.3.23, with Linus Torvalds mentioning ...
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502 views

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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4answers
2k views

Keeping a process running on server even SSH is closed [duplicate]

I am running long program on server, which is basically Jar file of java program. I want to keep this program running even if SSH terminal is closed, how I can keep this program running on server?
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2answers
417 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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4answers
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How to get the id of a very short child process if the parent is known?

I'm looking for a way to get the PID of a short child process in Linux. The process is instant from a human perspective. I know the parent process which will spawn the child process. Is there a way ...
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pkill can't kill processes with parent process id 1

I want to kill the following processes using pkill "run_tcp_sender.sh" or pkill -SIGKILL "run_tcp_sender.sh" root 14320 1 0 2012 ? 00:00:00 bash run_tcp_sender.sh ...
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3answers
145 views

how to run the dialog command with proccess

Please look on my code – ( bash script ) I want to display both dialogs on the screen on the same time, one dialog display the: tail –f from - /var/log/proccess1.log , and the second dialog ...
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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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1answer
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How is it that I can attach strace to a process that isn't in the output of ps?

I'm trying to debug why our integration tests are taking so long and it looks like they're hanging part way through. I logged onto our test service and saw the following behaviour: root@colossus:~# ...
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1answer
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Why does't stopping the nginx server kill the processes associated with it?

When I stop nginx like this on ubuntu 12.04, I get the following errors: $ sudo service nginx stop Stopping nginx: nginx. $sudo service nginx start Starting nginx: nginx: [emerg] bind() to 0.0.0.0:80 ...
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2answers
216 views

How to get environmental variables of a very short process?

I have a very short process for which i want to check the environmental variables for debugging purposes. The process is instant from a human perspective. The example illustrates it better. Example ...
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2answers
1k views

“ps” command doesn't return to prompt

I have this linux box that I need to maintain periodically. To do that, I issue a ps command programmatically and check the running processes. But as shown in the screenshot, sometimes, the ps ...
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2answers
885 views

Is there any impact of reaping zombie processes?

I will execute following command for reaping zombie /usr/bin/preap $(ps -ef | grep defunct | grep -v grep | awk '{ print $2 }' | xargs) Is there any service impact of this approach ?
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64 views

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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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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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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168 views

How can I get the pid of a process started this way

#!/bin/bash mkfifo /var/run/out while true do cat /var/run/out | nc -l 8080 > >( while read line do do some stuff done ) done How can I get the pid ...
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893 views

detect process eating cpu without: top, htop, ps?

I went thru a problem where I could only guess what process was eating the cpu. My cpu usage was about 80% for all cores at psensor. I tried htop, top and ps -A -o pcpu,pid,cmd --sort +pcpu (the ...
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1answer
180 views

How to find out a process gets end?

How can I tell when a given process exits? Like when it's done running and stuff. For instance: # Command 1 wget http://releases.ubuntu.com/14.04/ubuntu-14.04-desktop-amd64.iso # Command 2 echo ...
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244 views

How do I start a server via ssh and have it run after I log out?

I ssh into a virtual server and start up a web server. Everything runs as expected. But when I close my terminal on my laptop, the process dies on the virtual server. How do I fix this?
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772 views

How to kill a script which starts new processes?

The following is a Python application which spans a few threads, then spawns a new process of itself and exits: $ cat restart.py import os import random import signal import sys import threading ...
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696 views

Invoke a command/script disconnected from the controlling terminal?

I'm investigating the behaviour of a script that is normally run as an automated process (e.g. cron, Jenkins). The script can (eventually) invoke commands that behave differently (seeking user input) ...
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1answer
166 views

Alert when a process exits

I often download files using wget and cURL. Is there anyway I can make my Linux box give a visual alert when either of those processes exit (i.e: the download completes) PS : I am using Ubuntu ...
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2answers
124 views

Terminal command (called not from SU) that would restrict process from writting to all directories but one?

We have an app testApp. We have a folder called notRestricted in the directory where we run app from. We want to limit access of the app to file system so that app could write only to that folder (we ...
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2answers
116 views

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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2answers
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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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3answers
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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 ...