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

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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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When was a process started

To know when was a process started, my first guess was to check the time when /proc/<pid>/cmdline was written/modified the last time. ps also shows a START field. I thought both of these ...
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4answers
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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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0answers
38 views

How can I see a process' thread count? [duplicate]

Possible Duplicate: Is there a way to see details of all the threads that a process has in Linux? I want to see the thread count which belongs to a process in linux. What command should I ...
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3answers
4k views

What happens to suspended jobs in unix?

We can issue CTRL+Z to suspend any jobs in Unix and then later on bring them back to life using fg or bg. I want to understand what happens to those jobs that are suspended like this ? Are they ...
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1answer
770 views

Please explain the output from the jobs command

When I ran jobs command I see the following output : [1] - Suspended ./startWebLogic.sh [2] + Suspended (signal) top What does -/+ indicate in the second column ? ...
4
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3answers
2k 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 ...
5
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1answer
318 views

Can I add to my groups in the current (shell) process? [duplicate]

If I add myself to a group, it applies only to newly launched processes. Actually it's more restricted than that; it seems to apply only to new logins. I'm not sure what the exact mechanism is, but ...
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1answer
206 views

How to ensure a process has started reading a file before continuing?

I'm trying to write a command to test that data is written to a file. My first approach was: Start reading in the background. Write some data to the file. Wait for the reader to find a result. ...
5
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1answer
8k 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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2answers
909 views

How to view commandline of processes executed in last 10 seconds

Is there a view to log and list down the processes executed in last 10 seconds ? I especially want to trace the command line.
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1answer
357 views

Can I transfer running process from dead ssh [duplicate]

Possible Duplicate: How can I disown a running process and associate it to a new screen shell? I have started (as expected) a long copy process from ssh shell (putty) which died due to ...
3
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1answer
3k views

Cannot kill a java process

I have a java process that cannot be killed. I have tried every method I know, or that I have found on the internet to no avail. I have tried: killall java kill -9 <pid> kill -11 <pid> ...
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1answer
659 views

Very large values for utime and stime for foo. Is foo still running?

I am running a program foo It has been running for close to 30 days now (even more) Until around 10 days ago (I cannot be very exact) it used 100% of one cpu on my dual core laptop (it was at the ...
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vote
1answer
378 views

Application in terminal still running but not directly accessible [duplicate]

Possible Duplicate: How to suspend and bring a background process to foreground I have kind of an odd problem which I haven't encountered before. Here's what I did: I started an ...
0
votes
1answer
1k views

What does m represents in VIRT column using TOP command

When we run top command it shows all the processes information. But under VIRT column there is m written against some values what does that m represents, is it MB . If yes then why it is only showing ...
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2answers
3k views

What's the difference between lsof and fuser -uvm

Both shows the number of files we're using. Yet they both shows different results. root@host [~]# lsof /home4 root@host [~]# lsof /home2 root@host [~]# lsof /home4 Then we got fuser -uvm /home4 ...
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2answers
7k views

ATOP shows red line vmcom and vmlim. What does it mean?

utility atop shows: ATOP - MyServer 2013/01/07 00:03:57 10 seconds elapsed PRC | sys 2.18s | user 8.33s | #proc 141 | #zombie 0 | #exit 0 | CPU | sys 21% | ...
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3answers
2k views

Killing all the process of a command except first process

I am sometimes stuck in a situation where a script/command kept in Cron runs more than once because of some reasons (the first instance is not completed fully, the second instance of the same process ...
8
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1answer
525 views

What should interactive shells do in orphaned process groups?

(Re-posting in unix per the suggestion in http://stackoverflow.com/questions/13718394/what-should-interactive-shells-do-in-orphaned-process-groups) The short question is, what should a shell do if it ...
5
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1answer
626 views

How to know which commands are executed when I do something in GUI

This is for academic purpose. I want to know which commands are executed when we do something in GUI, for example creating a folder. I want to show that both the mkdir shell command and create folder ...
3
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2answers
1k views

What is meant by stack in connection to a process?

From the book Advanced programming in the Unix environment I read the following line regarding threads in Unix like systems All the threads within a process share the same address space, file ...
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1answer
3k views

Program stall under user but runs under root

I am running R job under a normal user john and root. Interestingly, the program stalls under john user but runs quickly under root. Using strace, I found that when john runs the R, the process stalls ...
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1answer
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How do I monitor opened files of a process in realtime?

I know I can view the open files of a process using lsof at that moment in time on my Linux machine. However, a process can open, alter and close a file so quickly that I won't be able to see it when ...
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3answers
261 views

How to view output for ALL processes simultaneously?

I know that you can connect to various background processes to watch their console output, but is there a way to view the output of all processes at once? Likely it would scroll quickly and be hard to ...
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5answers
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How to view the output of a running process in another bash session?

I have left a script running on a remote machine from when I was locally working at it. I can connect over SSH to the machine as the same user and see the script running in ps. $ ps aux | grep ...
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1answer
2k views

What is the `ucond` process state?

When debugging a program I saw that top -U username showed the following: 39769 eigenein 107 98 0 179M 38448K ucond 19 0:00 0.00% program What does it mean that a process in the ...
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2answers
344 views

What does the term static variable mean in unix speak?

From the section 2.7 of the book - The Linux programing Interface named Process memory layout : Data is defined as the static variables used by the program. What is the significance of the word ...
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2answers
127 views

What does d signify in processes like syslogd and httpd?

Why there is a "d" after the name of processes like syslogd and httpd ? What is its significance ?
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3answers
8k views

How does the set-user-ID mechanism work in Unix?

Can someone please explain the set-user-ID mechanism in Unix ? What was the rationale behind this design decision? How is it different from effective user id mechanism ?
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4answers
2k views

I want to kill all processes that result from the following command

The following command will display all the PID's running for vmstat1: ps -ef | grep "vmstat 1" | awk '{ print $2 }' My question is, how do I kill them all, if there's like 20 of them at once?
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2answers
194 views

receiving command as a parameter in bash

I have a following simple script called single-instance that executes the given command if there is no process under that command running. If I hard-code the command after the else statement, it has ...
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2answers
251 views

What's the mechanism that a process listening to localhost refuses to process a request to its LAN IP address?

The private IP address of my machine is 192.168.44.182. If I started a process using nc -l localhost 20000 Then this process won't handle requests sent to 192.168.44.182. Since the process ...
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1answer
204 views

vim not shown in fuser

First use Vim to edit a file, say /tmp/A. Assuming that vim process is the only one that accesses /tmp/A, then use "ctrl+z" to suspend the process, and execute fuser /tmp/A Then you see nothing ...
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4answers
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How can I find which process sends data to a specific port?

I have a service, keeping a certain port open. I'm getting data to it, that I neither expect nor want to get, and I'm trying to pin-point the source of this data. So how can I find which process that ...
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0answers
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Modify environment variable in a running process [duplicate]

Possible Duplicate: change environment of a running process Is there a trick to modify an environment variable in a running process? I need to add a repository at the end of PATH. I have ...
2
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1answer
68 views

remotely query text file associated with an instance of vi

I have opened several text files (a.txt, b.txt, c.txt, ...) in different sessions of vi launched from different instances of a bash shell. Having then accessed that machine remotely, I wish to ...
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2answers
9k views

Get PID of a function executed in the background [duplicate]

#!/bin/bash function abc() # wait for some event to happen, can be terminated by other process { sleep 3333 } echo "PID: $$" abc & echo "PID: $$" I need to retrieve the pid of this function, ...
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4answers
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What's the difference between running a program as a daemon and forking it into background with '&'?

What are the practical differences from a sysadmin point of view when deploying services on a unix based system?
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1answer
13k views

Stuck process: is it a bad sign?

Sometimes a few process are in a stuck state. For example: PID COMMAND %CPU TIME #TH #WQ #POR #MREGS RPRVT RSHRD RSIZE VPRVT VSIZE PGRP PPID STATE 99357 plugin-container ...
3
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3answers
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What process is sending TCP SYNs on Solaris 10?

Some process on my Solaris 10 machine is sending TCP SYNs to a remote machine. The remote machine never responds, so the connection is not established. How do I find out what process is initiating ...
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2answers
672 views

How to run linux process and come back to it later?

I'm trying to run a minecraft server on linux. Running the server starts an important interactive session. I can run the server in the background by appending & at the end of the command and log ...
2
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2answers
649 views

How to stop a infinite running process (ztail) started by a ssh session after that session is closed

I have a peculiar problem. My server supports multiple ssh session simultaneously, so that multiple admins can manage (via command line interface) it simultaneously. We have a command which calls ...
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votes
6answers
14k views

Is there a program that can send me a notification e-mail when a process finishes?

I am a computational scientist, and I run a lot of lengthy calculations on Linux. Specifically, I run molecular dynamics (MD) simulations using the GROMACS package. These simulations can take days ...
4
votes
3answers
950 views

Why does a default Linux installation run more processes than a default OpenBSD installation?

If I ps -aux on Ubuntu (or any GNU/Linux distribution) without GUI I see ~100 processes running. If I ps -aux on OpenBSD without GUI, then I get ~10 processes. What is the explanation/reason for ...
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4answers
300 views

“Virtual” shell, ie. jailing an user inside a process after the (SSH) login

The title might not say much about the issue at hand so let me get straight to the point. Let's assume I have a casual user who can log in to the system via SSH into a bash shell. I also have a PHP ...
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1answer
222 views

Is there any way to attach latrace to an already-running process?

I want to trace a running multi-threaded process's library calls. As of 5 November 2012, there's only one way to get ltrace to fully support tracing multi-threaded processes: you must check out and ...
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3answers
7k views

How to tell who is connected via vnc to my machine?

How do I check how many vnc connections or different users are currently connected to my machine? Only through wireshark? And how do I kill any other users connected through vnc?
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2answers
1k 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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1answer
927 views

Korn shell timeout/kill script

I am trying to write a simple Korn shell script to execute a loading process. The process occasionally runs into connectivity issues, so I need to kill it if it runs too long. I have been trying the ...