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

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262 views

End process from another SSH window

I forgot to use screen and I have a task that has been running for quite some time, and I do not want to lose the saved data. Basically Ctrlc will end the task and save the data if I am on the same ...
15
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2answers
6k 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 ...
7
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3answers
3k views

Silently start task in background

I know that you can use this to start a process in the background, without getting the notification when the process is put in the background and when it is done like so: (command &) &> /dev/null ...
20
votes
3answers
19k views

How to read environment variables of a process

Linux's /proc/<pid>/environ does not update (as I understand it, the file contain the initial environment of the process). How can I read a process's current environment?
5
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2answers
2k views

Where is the virtual memory stored on hard drive?

If a process wants to access a memory address that is not in physical memory, the OS outsources a page frame from physical memory to the hard drive for later use. Where on the hard drive is this data /...
8
votes
1answer
540 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 ...
4
votes
1answer
1k views

Difference between process group and job?

What's the difference between a process group and a job? If I type pr * | lpr then is it both a process group as well a job? What exactly is the difference between a process group ID and a job ID? ...
1
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2answers
2k 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) ...
1
vote
1answer
273 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 ...
16
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4answers
4k 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 -- ...
3
votes
3answers
4k 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 ...
5
votes
4answers
10k views

What is a command line alternative to top for finding current CPU utilization that isn't dependent on screen width?

If I run top -p <myPID> -n 1 with a terminal that isn't wide enough, the CPU utilization % is omitted from the output. When trying to find a process' cpu utilization via bash scripting, this is ...
1
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2answers
2k views

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 ...
3
votes
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> ...
0
votes
2answers
315 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 ...
24
votes
1answer
3k 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
votes
2answers
189 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 ...
11
votes
5answers
13k views

Under AIX, how can I get the full path of a program bound to a port?

Under Linux I can use netstat -tulpnw and ps, like so: # netstat -tulpnw | grep :53 tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN 1482/named udp ...
9
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1answer
1k 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
1k 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 ...
17
votes
2answers
795 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 ...
-4
votes
2answers
109 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 ...
1
vote
1answer
992 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 didn'...
8
votes
2answers
3k views

Dump process core without killing the process

Is there a way to get a core dump (or something similar) for a process without actually killing the processes? I have a multithreaded python process running on an embedded system. And I want to be ...
5
votes
3answers
4k views

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 ...
9
votes
3answers
32k 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 ...
8
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1answer
1k 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
121 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 ...
3
votes
2answers
1k 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 ...
3
votes
2answers
352 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 ...
5
votes
1answer
375 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
983 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 "...
6
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2answers
2k 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 ...
7
votes
1answer
7k views

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 ? ...
1
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2answers
195 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 ...
15
votes
4answers
91k views

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 ...
3
votes
2answers
825 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. ...
3
votes
2answers
944 views

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 ...
6
votes
3answers
2k views

What's the best way to determine the working directory for UNIX process using 'ps'?

I am running a Ruby command line script (rufus.sh)which ultimately calls Thread.new, which spawns a UNIX process as shown below. I run this script for more than 1 directory as the output of the ps ...
5
votes
1answer
1k 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 ...
13
votes
4answers
1k 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 ...
5
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2answers
29k views

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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0answers
39 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 use?
5
votes
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 ...
3
votes
1answer
806 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 ? ...
6
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1answer
888 views

Files bigger than max(off64_t) on Solaris, eg “/proc/../as”

How do I read or seek from a file that's bigger than the maximum off64_t? The problem arises because the address space of a process is represented in the /proc/.../as file, which is a huge sparse file ...
5
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1answer
334 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 ...
1
vote
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. ...
8
votes
5answers
7k views

Drop Process Privileges

I have a process that gets started by a damon running as root, now I want to "downgrade" this process's privileges to those of your average user. Is this possible? If yes how? PS: Running unix on a ...
1
vote
2answers
989 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.