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5
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3answers
3k views

What is a command to find priority of process in Linux?

How can i view the priority of a specific process ?
4
votes
2answers
198 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 ...
2
votes
2answers
623 views

`[java] <defunct>` with defunct children -> Any way to collect them?

Relating to question : What if 'kill -9' doesn't work? I have following situation : zombie process with threads, not collected by init : [root@Arch64]# ps auxH | grep java gwpl 569 ...
3
votes
1answer
48 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 ...
3
votes
1answer
46 views

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

I have some confusion as to whats 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 ...
1
vote
5answers
75 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 ...
1
vote
3answers
76 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
82 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 ...
25
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
51 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 ...
66
votes
2answers
5k 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 ...
167
votes
7answers
72k views

When should I not kill -9 a process?

I am always very hesitant to run kill -9, but I see other admins do it almost routinely. I figure there is probably a sensible middle ground, so: When and why should kill -9 be used? When and why ...
5
votes
3answers
431 views

Simple queuing system?

Given a commodity PC, we would like to use it to execute some tasks in the background round the clock. Basically, we would like to have commands like: add-task *insert command here* list-tasks ...
11
votes
1answer
4k views

What is the maximum value of the PID of a process?

What is the maximum value of the PID of a process? Also, is it possible to change the PID of a running process?
3
votes
2answers
2k views

How to find how many cores a process is using?

I have a eight core machine. How can I find out how many cores are used by processes that I see in htop?
2
votes
2answers
647 views

Removing zombie process from the process table

Can somebody please explain when parent process receives the exit status of a dead child process via wait, who actually reallocates the memory of the child process and removes it from the process ...
13
votes
2answers
15k views

How can I kill a <defunct> process whose parent is init?

Transmission is intermittently hanging on my NAS. If I send SIGTERM, it doesn't disappear from the process list and a <defunct> label appears next to it. If I send a SIGKILL, it still doesn't ...
9
votes
2answers
4k views

How to Throttle per process I/O to a max limit?

I'm looking for a way to limit a processes disk io to a set speed limit. Ideally the program would work similar to this: $ limitio --pid 32423 --write-limit 1M Limiting process 32423 to 1 megabyte ...
0
votes
2answers
104 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
3answers
204 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 ...
2
votes
1answer
66 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
227 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
27 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 ...
6
votes
2answers
3k views

How to check, which limit was exceeded? (Process terminated because of ulimit. )

Let's assume process runs in ulimited environment : ( ulimit ... -v ... -t ... -x 0 ... ./program ) Program is terminated. There might be many reasons : memory/time/file limit exceeded ; just ...
1
vote
2answers
53 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
70 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
105 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
107 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): ...
0
votes
2answers
76 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?
4
votes
3answers
641 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 ...
11
votes
9answers
3k views

Ensure a process is always running

I started hosting sites a while back using Cherokee. For external sources (FastCGI, etc) it has an option to launch the process if it can't find one running on the designated socket or port. This is ...
16
votes
4answers
1k 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
554 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
191 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
303 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
909 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
170 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
98 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
338 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
158 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 ...
11
votes
4answers
417 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
609 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
502 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
211 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
342 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 ...
5
votes
1answer
2k 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 ? ...
4
votes
1answer
432 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 ...
2
votes
3answers
3k views

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 ?
3
votes
3answers
1k 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 ...