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

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6
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2answers
5k views

How to see how many context switches a process makes?

I want to see if my process makes a lot of context switches. I also want to see how manpulating task groups affects the number of context switches.
0
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2answers
131 views

what is an application pool?

I'm reading this article: http://www.modrails.com/documentation/Architectural%20overview.html#web_app_models It talks about how Phusion Passenger extends Apache2 to act as an application server. ...
3
votes
1answer
151 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 ...
17
votes
4answers
10k views

How to attach terminal to detached process?

I have detached a process from my terminal, like this: $ process & That terminal is now long closed, but process is still running and I want to send some commands to that process's stdin. Is ...
2
votes
4answers
535 views

Process is eating all of the CPU time

Is there any magic command to track down which process is starting this perl task that is eating 100% of CPU time? I have this problem on several machines where JBoss AS is installed.
0
votes
1answer
89 views

What is meant by “a process has open handles to system objects”? [closed]

The following are qualities of a process: virtual address space executable code open handles to system objects a security context a unique process identifier environment variables a priority class ...
11
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2answers
3k views

Which process has PID 0?

I'm looking for the process started in Linux which has process ID 0. I know init has PID 1 , which is the first process in Linux, is there any process with PID 0?
5
votes
1answer
3k views

Execute Nohup command with input

In UNIX, I have a process that I want to run using nohup. However this process will at some point wait at a prompt where I have to enter yes or no for it to continue. So far, in UNIX I have been doing ...
3
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2answers
103 views

Current environmental variables of a process

This question relates to this answer. Is it possible to get the current (not initial) environmental variables of a process by making a child process and checking its initial environmental variables? ...
3
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3answers
59 views

Contents of stack area of a process

I've been going through some Unix text books and I can't have a clear picture on the contents of the stack area of the process. Can anyone please explain or point out some references?
-3
votes
2answers
142 views

Bash operator & not working [closed]

As per the bash reference, we can give a non-blocking command by ending it with an ampersand(&) character. However, when I try the below command its not working: python -m SimpleHTTPServer ...
2
votes
4answers
254 views

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 ...
2
votes
2answers
75 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 ...
4
votes
4answers
3k views

Running multiple nohup commands in background

Got two commands cmd1 and cmd2. Of the two, cmd2 takes longer to finish. Need to run cmd2 and then cmd1. Tried to run them in following way: bash$ (nohup ./cmd2>result2 &) && nohup ...
7
votes
3answers
638 views

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]/ ...
0
votes
2answers
241 views

what is a background process?

Here is a common definition of a background process: "A background process is a program that is running without user input. A number of background processes can be running on a multitasking operating ...
1
vote
1answer
80 views

Find if a process terminates in a specific amount of time

I am running a program.Inside this program i run a specific command and i use ulimit command to terminate the running of that command if it exceeds an amount of time.To be more clear i run this: ...
2
votes
1answer
184 views

pmap and memory usage

On Ubuntu 12.04, I have several apache2 processes running (the 1130 parent and the children it spawned), and as you can see, they have around 300-400 mb of virtual memory and 10 mb of resident memory: ...
0
votes
1answer
3k views

ps switches to display PID, PPID, PGID, and SID collectively

I tried ps with different kinds of switches e.g. -A, aux, ef, and so forth but I cannot seem to find the right combination of switches that will tell me the Process ID (PID), Parent Process ID (PPID), ...
1
vote
2answers
1k views

Zombie process cannot be removed or killed [duplicate]

I have a zombie process that refuses to be removed, have tried killall -9 1913 and pkill with no effect. Any help would be very much appreciated.Running Ubuntu 12.04.2 LTS. Thank you. ...
2
votes
1answer
57 views

Run a script when a process throws stderr message

I want to "wrap" a process around another to catch stderr messages when they occur. Use Case I'm using Compass and I have to have a terminal open and see if there is something wrong. My plan is to ...
1
vote
1answer
105 views

Deadlock in a crontab between cron and its child defunct processes

I'm having a strange case of deadlock, where the two processes launched by cron are defunct, but cron does not pick the return code and exit. I don't have access to the root user. myuser@myserver:~) ...
7
votes
6answers
3k views

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 ...
1
vote
2answers
335 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 ...
2
votes
1answer
396 views

what is the structure of a linux process? [closed]

what is the structure of a linux process? In linux there are processes executed on a address and which use system resources. Can anyone tell me the structure of a process and which parameter ...
52
votes
3answers
27k views

How do I read from /proc/$pid/mem under Linux?

The Linux proc(5) man page tells me that /proc/$pid/mem “can be used to access the pages of a process's memory”. But a straightforward attempt to use it only gives me $ cat /proc/$$/mem ...
3
votes
1answer
166 views

init: is it a user thread or a kernel thread?

init is the first task executed after kernel is loaded, right? Then who is its owner. also I can see [swapper/0] [swapper/1] ..... [swapper/7] having pid 0 PID PPID CPU TASK ST %MEM ...
5
votes
3answers
183 views

Determining the particular processor on which a process is running

I have access to an 8-core node of a Linux cluster. When logged in to the node, I can see a list of processors using this command: more /proc/cpuinfo In my 8-core node, the processors are numbered ...
4
votes
3answers
1k views

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 ...
4
votes
2answers
807 views

What is “automatic stack expansion”?

getrlimit(2) has the following definition in the man pages: RLIMIT_AS The maximum size of the process's virtual memory (address space) in bytes. This limit affects calls to brk(2), mmap(2) and ...
1
vote
2answers
640 views

How to watch pgrep?

When running a pgrep command with watch it does not only show the actual pgrep output, but also the watch process as well. Example: watch pgrep -lf donothing will show 3 processes, although ...
6
votes
7answers
5k views

Bash way to check if a process is already running in the background (and skip re-execution based on that)?

Can I make a bash command line that only runs a certain command if the process is not already running (in the background)? How do I check*, if a command is already running? (so I can add the next ...
5
votes
4answers
126 views

Best practices for job/process tracking and multi-tasking

I run 10+ different commands from 10+ different directories, and I need a better process to track everything. I do a lot of debugging, and often times I need to work on multiple issues in parallel. I ...
60
votes
6answers
18k views

Keep SSH Sessions running after disconnection

I sometimes have long running processes that I want to kick off before going home, so I create a SSH session to the server to start the process, but then I want to close my laptop and go home and ...
7
votes
3answers
22k views

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 ...
1
vote
3answers
100 views

How to know if a specific program is open

Using a command line in terminal, I want to be displayed 1 if a program (for example Firefox or Chromium) is open and 0 otherwise. Edit: By "open", I mean "is running on the current machine and has a ...
3
votes
2answers
141 views

Get PID of the application running in the active terminal emulator

My end goal is to be able to open a new terminal window (urxvt) directly in the current working directory of the program running in the window currently active. I'm currently using the shell (Bash), ...
4
votes
1answer
129 views

Raise Brightness When Maximizing Terminal

I'm looking to raise the brightness when I maximize or foreground the Terminal window which has Vim running. I would like to reset the brightness to normal when I minimize or background that process ...
2
votes
1answer
440 views

How to check if a currently running process is opened by root or user

I'm currently creating a BASH script to kill off processes. I first check if the process is running then kill it. But I would like to add a nested if to find out if that process was opened by root ...
1
vote
2answers
524 views

How do I kill 'repo sync' using crontab given it spawns many processes?

I need to 'repo sync' the Android source overnight, as my monthly bandwidth is limited. , I start the 'repo sync' at midnight, then want to kill it at 8am. The following is the command: 2 0 * * * ...
4
votes
3answers
606 views

What is a process GID and what purpose does it serve?

Reading mod_wsgi's documentation I found you can choose which group to run the worker processes as. I can understand group ownership of files and how only a user who belongs to that group can achieve ...
0
votes
1answer
171 views

Identify Tasks/Process which are 7 days old in linux

How can I identify the processes running since 7 days in Linux?
1
vote
1answer
573 views

How to kill the (last - 1) PID with bash

I know how to kill the last process with kill $! However I would like to kill the last−1 process, i.e. not the last one, but the one before the last one. I tried kill $$(($! -1)) but ...
1
vote
1answer
171 views

How to kill all processes that don't have specific parent process?

A parent process should always be running with N children process. I would like to run a script which will show/kill all children processes that don't have a parent process. $ ps faux | grep ...
1
vote
2answers
187 views

process memory usage

What is usually meant by the phrase process memory usage, what does this actually mean, i.e. what does this memory consist of? And what column does it correspond in ps aux output, RSS or VSZ?
3
votes
2answers
172 views

Is grandchild process also child process?

In Unix/Linux terminology, do child processes of a process include grandchild processes of the process?
5
votes
3answers
207 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 ...
0
votes
2answers
693 views

`ps | grep | kill` aborts my script prematurely [duplicate]

I have a Linux computer that I remotely SSH into using plink on a Windows XP machine. I have the Plink program set to execute commands in a script using automated login: plink -ssh [domain name] -l ...
3
votes
3answers
227 views

Print process ID (PID) of a Matlab instance

To run my Matlab scripts, I've created a shell script to which I give two parameters - the path to the matlab file ($1) and to the log file ($2): nohup time matlab -some_parameters -r "run $1;exit" ...
2
votes
4answers
195 views

Open program as root, close root session but still program is running

When I run my backup script, first I switch to root, mount a truecrypt partition and then run the script. I've noticed that after run truecrypt as root, I can exit the root session and truecrypt ...