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

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Find and remove large files that are open but have been deleted

How does one find large files that have been deleted but are still open in an application? How can one remove such a file, even though a process has it open? The situation is that we are running a ...
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1answer
138 views

What rules govern the parent-child relationship of processes launched by shell across a pipe?

#!/bin/ksh # start_service: start the service my_server_executable 2>&1 | my_pipe_following_shell_script & exit 0 After I run the above start_service script from command line, it is ...
3
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3answers
1k views

What after exec() in ls command. Is the parent process printing the output to the console or the child?

I have a simple doubt on execution of the command ls. As per my understanding from the research I have done on the internet, I understood the below points. When we type ls command shell interprets ...
12
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4answers
603 views

Is there a top-like command that shows the network bandwidths and file accesses of running processes

For example, we'd like to see: PROCESS IF TX RX FILE(regular) R/W prog1 eth0 200kB/s 12kB/s -- -- wlan0 12kB/s 100kB/s -- ...
8
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3answers
1k 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]/ ...
4
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1answer
5k views

Linux : See CPU usage by a process for the last second

vmstat 1 Above will print virtual memory statistics each seconds. It will also show the CPU utilization for last second. I have a web server at hand which runs httpd and MySQL. I need to find how ...
5
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1answer
4k views

Elegantly get list of children processes

I would like to get a list of all the processes whose parent is $pid. This is the simplest way I've come up with: pstree -p $pid | tr "\n" " " |sed "s/[^0-9]/ /g" |sed "s/\s\s*/ /g" Is there any ...
3
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1answer
3k views

What does kill 0 do actually?

In the man page, it says: kill [ -s signal | -p ] [ -a ] [ -- ] pid ... pid... Specify the list of processes that kill should signal. Each pid can be one of five things: 0 All ...
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2answers
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multiple background processes in a script

Suppose if i have a situation in which some files need to be copied and it takes long time so i would have to go for parallel processing of the file copy. for example it may look like this for i in ...
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4answers
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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 ...
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3answers
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Why does Firefox refuse to die despite killing it with pkill -9?

I am issuing the following command to kill Firefox on my Red Hat Linux box: [subhrcho@slc04lyo ~]$ pkill -9 -f firefox [subhrcho@slc04lyo ~]$ However, when I try to invoke Firefox through ...
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2answers
172 views

Which process updates /proc/scsi/scsi?

I wrote C that displays info about my hardware on ubuntu. Now I wonder how I can make it more flexible such as querying the hardware directly instead of the file the os updates. So I think I can look ...
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1answer
1k views

How does systemd survive a kill -9?

Between the recent "Why does 'kill -9 0' end my console session" and "How to get a kernel panic" questions, I got a bur under my saddle and tried kill -9 1 on a mostly up-to-date Arch linux laptop. I ...
2
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2answers
146 views

what happens when a window manager is put to background

I am trying to understand the situation why .xsession file expects the last process to be in foreground otherwise it is supposed to stop X11 session. I have a small stand-alone script. when I run ...
7
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1answer
559 views

Why does “kill -9 0” end my console session?

I just wonder why kill -9 0 ends my tty console session? What exactly is PID 0, it is not listed on a ps aux?
3
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4answers
692 views

Capture complete process structure/stack

There are a lot of java processes running on the server, generally, we capture the PIDs of the java processes using command 'ps -ef | grep java'. In general, the java processes have a lot of jars in ...
15
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2answers
558 views

How are the processes in UNIX numbered?

I can't find any pattern when I look at the numbering of PIDs in process table (ps -a), as the PIDs are not subsequent numbers and sometimes there are large "gaps" between those numbers. Is it ...
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2answers
88 views

Which Linux distro/mode offers lowest interference when running your own applications?

I'm interested in a Linux distro to build C projects and test their behavior in a very predictable and controlled environment. I'm especially concerned about letting the scheduler deal as much as ...
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2answers
2k views

Why does bash show 'Terminated' after killing a process?

Here is the behaviour I want to understand: $ ps PID TTY TIME CMD 392 ttys000 0:00.20 -bash 4268 ttys000 0:00.00 xargs $ kill 4268 $ ps PID TTY TIME CMD 392 ttys000 ...
5
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2answers
6k views

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 ...
2
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3answers
8k views

Kill only one Java process

I usually run few Java applications, one for server running locally and other for some IDE like NetBeans. And from time to time, after lots of redeployments, my server get stuck on ...
5
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3answers
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How to track the number of processes and forks per user?

I need to figure out how many forks are done and how many concurrent processes are run by each user over time. It does not look like this information is tracked by my distribution. I know how to ...
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1answer
467 views

Change of real time priority made no visible effect

we were trying to get the best result with software PWM on raspberry pi with Raspbian. We made a python script which starts PWM on a GPIO pin, and observed the results with the oscilloscope. It ...
7
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1answer
478 views

Real time priorities in non real time OS

If I do the following command on my standard Linux Mint installation: comp ~ $ ps -eo rtprio,nice,cmd RTPRIO NI CMD ... 99 - [migration/0] 99 - [watchdog/0] 99 - [migration/1] - 0 ...
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2answers
99 views

Cron creates vim process but does not display vim

Under MacOSX 10.8.2 I am able to run vim as follows in the bash shell: /usr/bin/vim -c "normal G" -c 'startinsert' ~/.journal If I put the exact same command in a script: #! /bin/bash export ...
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2answers
532 views

Which script from /etc/init.d/ started the process?

Let's say we have a PID of a process and we know that it was started by init during startup. How do we find the script name that started it? One way is to run grep $PROCESS_NAME /etc/init.d/*, but ...
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2answers
1k 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 ...
5
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1answer
170 views

How to monitor all executions of an executable over a time period

I know how to monitor a process. Commands like top and so forth can monitor the CPU time and memory usage for a given process instance. But say I expect a given executable to be run several times in ...
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2answers
548 views

Host process for multiple processes?

I am maintaining an application that currently consists of 4 processes that are dependant on each other in various ways. At the moment these processes are started, stopped and monitored via a rather ...
7
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3answers
314 views

Why is I/O uninterruptible?

What is the rationale behind making I/O uninterruptible? What would be the negative consequences if a process handling I/O were allowed to handle a signal?
4
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2answers
1k views

Why “uninterruptible sleep” is not counted as “IDLE”?

When I run top -bi, where the parameter -i means "ignore idle processes", the resulted list(see below) of processes are either R or D, although there're S processes at that time. So, why ...
5
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1answer
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What does <defunct> mean in the output of ps?

I had issued the ps -ef|grep java command and this is one of the entries that I got : subhrcho 875 803 0 Jan23 pts/5 00:02:27 [java] <defunct> What is <defunct> implying here ? ...
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Please explain the -f option in pgrep

man pgrep says the following about -f option: -f The pattern is normally only matched against the process name. When -f is set, the full command line is used. What does it ...
4
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1answer
582 views

What is the difference between exiting a process via Ctrl+C vs issuing a kill -9 command?

I know I can kill any process with kill -9 command . But sometimes i see that even if I have terminated a program with CTRL+C , the process doesn't get killed . So I want to know the difference ...
5
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4answers
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How do I know what service is running on a particular port in linux?

I am trying to run weblogic server on my linux machine and I am getting the following error : ERROR: transport error 202: bind failed: Address already in use ERROR: JDWP Transport dt_socket failed to ...
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2answers
318 views

$BASHPID And $$ differ in some cases

I'm reading "BASH pocket guide of Oreilly". It said: The process ID of the current Bash process. In some cases, this can differ from $$. Above explanation , explained $BASHPID variable. ...
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2answers
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Please explain this output of ps -ef command?

A part of the output from the ps -ef command is given below : UID PID PPID C STIME TTY TIME CMD root 1 0 0 2012 ? 00:00:01 init [3] root 2 ...
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3answers
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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 ...
13
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4answers
712 views

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
36 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 ...
4
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3answers
2k 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 ...
2
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1answer
402 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 ? ...
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2answers
982 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
182 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
177 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. ...
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1answer
4k 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
460 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.
2
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1answer
257 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
1k 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> ...