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0
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0answers
23 views

Where does the process go after changing to state TASK_STOPPED in Linux? [closed]

Supposed that we have a runnning process in Linux system, the state of that process will be TASK_RUNNING, after that if It receive the SIGSTOP signal , the process's state will change to TASK_STOPPED. ...
0
votes
0answers
72 views

Detach a process from Sh (not Bash) or “disown” for Sh (not Bash)

Consider a shell script executed by Sh, not Bash (and I can't change it, and can't use a shebang, it's ignored). The & operator works, but disown $! does not and makes Sh complains “disown: not ...
5
votes
2answers
71 views

How can I see i/o stats for a briefly running process?

For long running processes like init, I can do things like $ cat /proc/[pid]/io What can I do if I want to see stats for a briefly running process such as a command line utility like ls? I don't ...
0
votes
2answers
44 views

Idiomatic way to kill -9 only if “graceful” way doesn't work?

Is there a common way or existing utility to do the following? kill a process Give it a few seconds to shut down gracefully kill -9 it if it hasn't stopped
3
votes
1answer
69 views

Process management and pkill

I've been studying process management using shell scripts and I'm starting to realise how difficult it is to make sure that it's done right. For example, you can record the PID of a program to a ...
1
vote
3answers
45 views

How can i get the process with the biggest pid?

How can I get the process with the biggest pid using ps?
3
votes
1answer
94 views

SIGKILLing after a grace period

I've seen a lot of process managers that try to do this. It was my understanding that you should only use SIGTERM to kill a process. The process could take an unknown amount of time to clean up after ...
0
votes
1answer
39 views

How can I make my command more susceptible to system slowdowns so as to use it as a visual QoS widget on my desktop?

I had some system slowdown event1 after mistakenly using a command so I thought I could use a desktop "widget" to visually show quality of service or at least show when QoS was degraded and get some ...
7
votes
2answers
319 views

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 ...
2
votes
1answer
74 views

kernel event listener

I wonder if there is something similar to an event listener in UNIX that a program can subscribe to? Specifically I want to know: Start and end times of a user session Start and end of the ...
2
votes
1answer
59 views

how to know the use of my applications?

I want to know how long my programs have been used. For example if I use my web browser I want to know the start and the close time to obtain a total of use time. Basically I want to know when an ...
4
votes
2answers
153 views

Process owner vs process user (Gnome's system monitor)

Gnome's system monitor has a "User" column in the Processes tab. There's also an "Owner" column, (that seems to be hidden by default). Most of the processes have the same values on both columns. ...
4
votes
1answer
59 views

How to detect a desktop application hanging

I want to write a script that will detect whether a particular desktop application is responding and kill it. Is this possible? I know I've seen the GNOME desktop put up a "Application is not ...
11
votes
2answers
864 views

What does a niceness value of (-) mean?

According to the man page, and wikipedia; nice ranges from -20 to 20. Yet when I run the following command, I find some processes have a non numerical value such as (-). See the sixth column from ...
3
votes
1answer
106 views

What's the correct value to base the maximum number of CPU's to sched_setaffinity to?

I have some confusion as to what's the correct value to use for the number of CPU's I can use to make a CPU_SET for a sched_setaffinity call on my system. My /proc/cpuinfo file: processor : 0 ...
4
votes
1answer
88 views

Reporting cpu hogs

Once in a while some program (ok, usually it's firefox) will start eating up nearly 100% of a processor's cpu time, heating up the processor and driving down by laptop's battery life. Since it's not ...
1
vote
3answers
154 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?
4
votes
1answer
146 views

What is the default or most commonly used multiprocessing model in Linux? Symmetric or Asymmetric?

What the multiprocessing model for Linux? Is there a default or most commonly used model? Is it similar or very different from say BSD or even the MS Windows kernel? If SMP is used normally, can ...
2
votes
5answers
195 views

Replace instance of process in place?

I suspect this is not doable just because of the security implications, but here's what I'd like to do. Basically we run a bash shell-script on our CentOS server that calls Program-A (in our case ...
26
votes
4answers
2k views

python vs bc in evaluating 6^6^6

I am evaluating the expression 6^6^6 using python and bc separately. The content of the python file is print 6**6**6. When I execute time python test.py, I get the output as real 0m0.067s ...
3
votes
1answer
104 views

Better way to kill all processes with a handle to some file

This kills every process with a handle to file /foo/bar (in bash): lsof /foo/bar 2>&1 | grep "/foo/bar" | sed "s/ */\\t/g" | cut -f 2 | while read PID; do kill $PID; done This does not ...
70
votes
2answers
6k views

How does Linux “kill” a process?

It often baffles me that, although I have been working professionally with computers for several decades and Linux for a decade, I actually treat most of the OS' functionality as a black box, not ...
4
votes
3answers
1k views

Why do top and ps show different PIDs for the same processes?

When I run top -H, I see that my multiple mysql threads all have the same PID. However, in ps -eLf I see each one has a different PID: ps -eLf UID PID PPID LWP C NLWP STIME TTY ...
0
votes
2answers
185 views

Calculating CPU time of process in RHEL 5.3

For a process management,I would need to remove a process that exceeds a certain amount of CPU time, for example 1 hour.In PS command ,it has TIME parameter shows the total CPU time of a process .So ...
2
votes
1answer
97 views

Process overwrite access restriction

I want to run a program so that it can only create new files and not overwrite existing ones. Does something like this exist? $ fsaccess --can read,write --not overwrite --command bash -c 'echo ...
5
votes
3answers
576 views

Using `kill -s 0 $pid` vs `[[ -e /proc/$pid ]]` to detect if PID is running

One of the idioms often used to check if process is running is to use kill -s 0 $pid. My question is, does it have any upsides over using [[ -e /proc/$pid ]] construct? The script I'm writing is ...
0
votes
0answers
41 views

What could keep a process in 'Runnable' state indefinitely?

I am developing for embedded Linux and I have found a critical bug when stability test is performed. After 1-3 days running at some points the system becomes inoperative. Kernel network stack keep ...
1
vote
2answers
59 views

What information about a process is retrievable after it is terminated? [duplicate]

After a process has been terminated, is it possible to retrieve any information about it, such as when it started and finished, &c. Is it possible to enable logging of this information?
3
votes
3answers
84 views

Disallow File IO for a process except for FIFOs

How do you start a process that cannot do any file IO (opening / closing files, creating / deleting files, reading / writing files, etc.), except to read and write to pre-created FIFOs? (chroot will ...
2
votes
2answers
270 views

How to make processes not die after its parent dies?

I've been messing with forkbombs and noticed that if I just fork() processes repeatedly, killing the initial process will bring down the whole tree. This is not the case for forkbombs written in BASH ...
1
vote
2answers
145 views

KDE becomes slow

I experience problems with KDE 4.11.1 on Arch Linux. It suddenly becomes laggy and unresponsive and just as suddenly returns to the normal state after some time. Normal CPU load (KSysGuard): ...
9
votes
3answers
2k views

What's the difference between pkill and killall?

I know that pkill has more filtering rules than killall. My question is, what is the difference between: pkill [signal] name and killall [signal] name I've read that killall is more effective ...
0
votes
2answers
144 views

UNIX- Identify which processes are running more that 6hours

I need to know which processes are running more than 6 hours in UNIX. How can I find those out?
17
votes
4answers
2k views

What happens if you edit a script during execution?

I have a general question, which might be a result of misunderstanding of how processes are handled in Linux. For my purposes I am going to define a 'script' as a snippet of bash code saved to a text ...
0
votes
1answer
761 views

Rsync from multiple folders to one

Is it safe to have multiple folders Rsync simultaneously into one? Each of the source folders contains a subset of the destination folder, and everybody just syncs into a master destination folder. I ...
3
votes
2answers
330 views

Why can't pgrep find scripts started via env?

For example: $ cat foo.sh #!/usr/bin/env bash while true; do sleep 1 ; done $ ./foo.sh & $ pgrep foo.sh $ Contrast with: $ cat bar.sh #!/bin/bash while true; do sleep 1 ; done $ ./bar.sh & ...
1
vote
2answers
587 views

Mysterious bash instances using a lot of CPU, how can I debug?

I seem to have multiple bash processes running that are taking up most of my CPU. This is the output of top -c: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 20116 ...
2
votes
2answers
3k views

Find the process id of a java application in a bash script (to see if the target application is already running)

I know there are a million questions on getting the process ID, but this one seems to be unique. Google has not given me the answer, so I hope stackexhange will help rather than close this question. ...
3
votes
2answers
246 views

Running a daemon as a non-privileged user

I am trying to set up a Thin Ruby application server on my Ubuntu VPS. I have created a specific account, installed rbenv under it along with all gems. I am looking for a convenient way to obtain the ...
1
vote
0answers
27 views

Building a process Watchdog [duplicate]

I intend to write a process watchdog that runs out of cron or similar that watches all of the core processes denoting things like run state, VMstat, Inet operations and reports it to a file or ...
4
votes
1answer
133 views

Understanding when background process gets terminated

I have a script which starts a number of background processes and if works fine when called from the cmdline. However the same script is also called during my xsession startup and additionally on ...
4
votes
1answer
637 views

A script's background process is still alive after closing the terminal

This is more of a process management/signal handling question than a Bash question. It just uses Bash to explain the issue. I'm running a Bash script in which I run a background process. This is the ...
2
votes
2answers
194 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 ...
12
votes
4answers
604 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 -- ...
1
vote
2answers
1k 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 ...
15
votes
2answers
559 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 ...
1
vote
1answer
358 views

Managing the output streams of many subprocesses with deadlocks

I have a Python script that does more or less this current_tasks = TaskManager() MAXPROCS = 8 while len(outstanding_tasks) > 0: if len(current_tasks.running) < MAXPROCS: ...
1
vote
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 ...
4
votes
2answers
302 views

How can I synchronize processes started in different TMUX panes?

Consider this: tmux split-window -d program1 program2 # this program depends on some side effects produced by program1 In this case, program2 will start before program1 is ready. program1 will send ...
5
votes
1answer
3k 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 ? ...