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

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Print pids and names of processes as they are created

From the question here, the OP wants to repeatedly poll the pid of a process using pidof in a shell script. Of course this is inefficient as a new process must be started for the pidof program ...
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57 views

Are there any alternatives to pidof? (smaller footprint)

Well, I've just found out that with extensive usage of pidof in very short intervals, the seemingly tiny tool can be a great CPU hog. (Source: top) On my older machine, it can easily reach 30 percent ...
2
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2answers
62 views

set packet rate limit via iptables

I have a packet rate limit (max. 10 per seconds) which is set by my internet provider. This is a problem if I want to use the AceStream player, because if I exceed the limit I get disconnected. How ...
7
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4answers
319 views

How to find source of spawning process?

I have a Java process running on a RedHat Linux instance. The problem is it keeps reappearing after I kill it. I am not sure where to look. I've already went to crontab, but no luck. I've looked at ...
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1answer
5 views

What is the meaning of every column when executing psig command?

I try to use psig command to track signal dispositions of a process on Solaris: bash-3.2# psig 3109 3109: bash HUP caught termsig_sighandler 0 ...
3
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1answer
28 views

How to find the file corresponding to a pipe opened by a process? [duplicate]

I created this script, which listens for characters received on a hardcoded pipe, and tries to eval those characters. I call my script loop_executor.sh This is all it contains: !/bin/bash while : do ...
3
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3answers
79 views

How to get whole command line from a process?

How can I get the command arguments or the whole command line from a running process using its process name? For example this process: # ps PID USER TIME COMMAND 1452 root 0:00 ...
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0answers
11 views

How do I find the resident memory size of a process on busybox?

I run top on busybox and it shows all processes and their virtual memory size. How do I determine how much RAM is being used by each process?
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32 views

Kill a whole process tree regardless different GIDs

I am having issues with process control using the signals available to the process abstraction. In the example below you can see there is a perl script which is the parent of the whole tree with a ...
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13 views

How does the parent select which forked child process to communicate with? [migrated]

I created several child processes from one parent, and I also created bidirectional pipes between each process and the parent. Now the problem is how can I go back and forth between the child ...
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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. ...
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1answer
17 views

Types of sleep modes for processes

I came across this while troubleshooting why our server is doing down everytime the oracle process is killed. I listed the oracle process running on the server using ps aux | grep oracle and here is ...
3
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1answer
52 views

Why does the 'user' and 'sys' time vary on multiple executions?

There is a nice question and answer explaining the relationships between 'real', 'user' and 'sys'. It explains the reasons why 'real' can vary, and defines the 'user' and 'sys' as times the process ...
2
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1answer
53 views

How to change the kernel max PID number? [duplicate]

The default PID max number is 32768. To get this information type: cat /proc/sys/kernel/pid_max 32768 or sysctl kernel.pid_max kernel.pid_max = 32768 Now, I want to change this number... but I ...
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0answers
26 views

Why aren't the argv and envp arguments to execve pointers to const? [migrated]

Take e.g. execve(2), which according to posix has this prototype [1]: int execve(const char *path, char *const argv[], char *const envp[]); To me, it seems as if int execve(const char *path, const ...
2
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2answers
49 views

How can I make a for loop starting a lot of processes?

I want to test some bug, and to do that I need to have a situation where the PID is larger than 99999. I am thinking of a bash script, a for loop. Any ideas?
6
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1answer
279 views

Is there a way to see if process listening on TCP port receives a message?

According to tcpdump, my server receives the following TCP packet: 12:52:29.603233 00:19:e2:9e:df:f0 00:16:3e:6a:25:3f, ethertype IPv4 (0x0800), length 74: 10.10.10.65.38869 192.168.215.82.22: ...
0
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2answers
46 views

What determines if an executable can be run in different independent processes simultaneously?

I posted a question about how to run an executable (a PDF viewer) under wine independently in multiple processes (independent means no communication between them, it is not parallel computing). I ...
0
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1answer
42 views

Kill unresponsive process by name but preserve responsive processes

For some reason, I end up with a fair few Google Chrome Helper processes which stop responding, hogging CPU resources. Usually I just run killall Google\ Chrome\ Helper, however this kills all, ...
2
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0answers
46 views

Why do some processes pass on their cpu usage to another process when it ends?

I have wondered this for a while. For example, lets say process1 is a process that uses a lot of cpu power, like 90%. Its a video game. Then i have process2 which uses 10-12% cpu. Its a web browser. ...
2
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1answer
36 views

w command for the other network hosts

While the who command refers to the local machine, rwho shows the same informations about all the known hosts of the local network. Similarly, w shows informations about the users on the local ...
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2answers
42 views

How to trick an application to run different processes?

I am running PDFXCview.exe (for pdfxchange viewer portable version) under wine to open a pdf file, by PDFXCview.exe 1.pdf When I do the same for another file, the other file will be opened by the ...
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3answers
1k views

How can I see the exact command line being executed inside some bash instance?

I have a long running bash instance (inside a screen session) that is executing a complex set of commands inside a loop (with each loop doing pipes, redirects, etc). The long command line was ...
29
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4answers
2k views

Is there any UNIX variant on which a child process dies with its parent?

I have been studying the Linux kernel behaviour for quite some time now, and it's always been clear to me that: When a process dies, all its children are given back to the init process (PID 1) ...
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2answers
46 views

How to get a procesess's actual memory usage (including data in swap)

I'm trying to check how much memory strain a process is actually putting on the system, but ps, top and friends are almost useless for that purpose as they only report 3 statistics: RES - the ...
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3answers
513 views

Cron job to check if PHP script is running, if not then run

I am wondering if someone might point me in the right direction. I've got little experience working with the Linux command line and recently due to various factors in work I've been required to gain ...
6
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1answer
158 views

What's the purpose of the /proc/pid/mountinfo file?

What's the purpose of the /proc/pid/mountinfo file (with pid being numerical process id)? As far as I can see it reflects contents of the /proc/mounts file but with added information. Also the file ...
3
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2answers
90 views

Kill a process that keeps restarting

What if 'kill -9' does not work? or How to kill a script which starts new processes? doesn't help me in anyway. I have a python script which starts automatically with another process id using ...
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0answers
14 views

Terminal output from a program not opened in terminal [duplicate]

Using bash on Ubuntu, I can launch programs from command line and watch what the program is doing 'in the background' while I use the GUI frontend. This is particularly handy when a GUI progress bar ...
0
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1answer
23 views

Using $BASHPID in grep statement

I'm trying to exclude the PID of the subshell from the results returned by pgrep. Note that the name of the file is the same as the name passed to pgrep. Why does setting a variable equal to BASHPID ...
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1answer
36 views

How can I determine what individual ulimit constraint a process has?

I have a service that sets a custom limit for open files (ulimit -n 5000) as part of its init script. My understanding is that this will be effectively for the service and its child processes. Since ...
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2answers
272 views

How can I tell when a process has finished writing to a file?

I have a process which has been spawned from a shell. It is running as a background process and exporting a DB to a CSV file in /tmp. How can I tell when the background process has completed ...
0
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1answer
28 views

What are the potential negatives of turning on process accounting (psacct package)?

I am looking into turning on process accounting on some EL6 servers. What are the potential pitfalls of turning this on? If you mitigate storage requirements with log rotation, any reason you would ...
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30 views

If I use one of the exec family functions to open a child process, will pipes to parent be applied to the child?

Say I open a parent process with a master process that assigns the stdout to a file for logging. Then say I use the parent process to open a child with execvp (or any other of the exec family of ...
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0answers
50 views

Strange cpu usage values reported by pidstat

I have a script that reports the cpu usage of a specific program reading values from pidstat. The script launches as: pidstat -C ^frontend$ -h -l -p ALL 1 1 The values reported this way sometimes ...
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3answers
55 views

Run linux process at very very low priority?

I have regular process that not so important but will consume so much CPU power, and I have another process which is really important, but it spend most of the time idle, but when it got a job it ...
0
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1answer
23 views

Background Process not running?

I ran a C program with an infinite while loop in a terminal and observed one of the CPU cores shot to 100% usage. When I turn it into a background process using Ctrl+z, the CPU usage suddenly dipped ...
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2answers
47 views

How to run the dialog command with proccess?

NOTE: Please look at my code, it's a Bash script. I want to display both dialogs on the screen at the same time, one dialog displays this: tail –f from - /var/log/proccess1.log and the second ...
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1answer
44 views

Deterministic method to find out whether some other process is in a chroot jail and where?

NOTE: I'm familiar with this U&L Q&A titled: How do I tell I'm running in a chroot? that sounds similar to what I'm asking, but there's a subtle difference to what I'm looking for. That ...
4
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1answer
36 views

How can process doing “vfork without exec” end up in a long uninterruptible sleep?

In this answer user suggests that Normally, Uninterruptible sleep should not last long, but as under windows, broken drivers or broken userpace programs (vfork without exec) can end up sleeping ...
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1answer
26 views

Empty kernel processes on CentOS vps : 2 different servers

I'm not sure I'm asking correctly, or perhaps I'm just looking at the wrong things. I'm migrating from one CentOS Vps (on an OpenVZ box) to another CentOS VPS (on a VMWare box). VPS #1 = CentOS ...
4
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1answer
61 views

How to completely detach a process

I want to spawn a process and run it at the top level so that when the shell exits, the process keeps running. I had mistakenly thought that nohup would do this, but when I exit from the shell (the ...
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2answers
217 views

Why does process substitution result in a file called /dev/fd/63 which is a pipe?

I am trying to understand named pipes in the context of this particular example. I type <(ls -l) in my terminal and get the output as, bash: /dev/fd/63: Permission denied. If I type cat <(ls ...
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1answer
81 views

Process ownership on linux changes to root when the user tries to kill the process

We have a bunch of RHEL machines which all run an application binary that is owned by root and has SUID set. Let's say user X starts the application, the process starts with PPID 1, since SUID is set ...
5
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1answer
107 views

Is the Unix process scheduler itself a process?

Is the Unix process scheduler itself a process, or does it piggyback on other processes in the same way a system call does (running kernel code in the user process with the kernel bit set)?
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1answer
43 views

Comparing Windows and Linux machine hardware

I have to compare Linux and Windows machine hardware? In windows system, I can open the My computer properties and see the details like processors, RAM Hard disks etc. Through task manager, I can see ...
9
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1answer
215 views

Why does the location of Enviroment Variables vary that much?

Reading the book Hacking: The Art of Exploitation by Jon Erickson, I am trying to approximate the address of an environment variable SHELLCODE to exploit a program. Every time I run ...
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2answers
44 views

Process auto starts itself not by cron

My linux server was hacked. and now there is a file in root directory that generates big traffic. when i kill this process it autostarts itself again. then i did chmod -x. but it returned x option. ...
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1answer
78 views

Real time processes scheduling in Linux

I have been learning some scheduling concepts. Currently my understanding so far is as below. There are real time processes and non real time processes. Non real time processes can have nice values ...
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1answer
44 views

How logical address of one process differs from the logical address of another?

I am a newbie. I am reading Understanding Linux Kernel. There, I am trying to understand how logical address got translated to physical address. To my understanding, I believe logical address got ...