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

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Why are the process priorities not respected?

I was running four jobs in the background with HTCondor. It sets the priority to 10. Then I was compiling something with make -j4 in the foreground (priority 0). However, the HTCondor jobs still got ...
2
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1answer
53 views

The current path of a process

Suppose I write a program, which outputs a file under a relative path (as opposed to a full/absolute path) - let's say, the current path. Then I compile it and store the executable under some dir ...
4
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1answer
521 views

Maximum memory usable by a 32 bit RHEL 6 system

I have installed a 32 bit RHEL OS on a 64 bit system. From the wiki page of PAE: The Linux kernel includes full PAE mode support starting with version 2.3.23, with Linus Torvalds mentioning ...
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3answers
23k views

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 ...
0
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1answer
50 views

Process's father after setpgid(0,0);

I have a process P1 (child of some parent process P0) both in the same process group. P1 somewhere in his code runs: setpgid(0,0); then a new process group is created (where the group leader is P1). ...
2
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1answer
63 views

Does this dispatcher produce zombie process?

I have such a dispatcher shell script. while read line do java TestProg $line & done < $tasklist On the zombie process Wikipedia page, it says if a parent fails to call wait, the ...
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4answers
896 views

chdir(<directory>) doesn't change directory after exiting to shell

I wanted to make a simple C program to change to my project directory. Its content is following: #include <unistd.h> int main(){ chdir("/home/enedil/projects/algo"); return 0; } I ...
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2answers
239 views

Is grandchild process also child process?

In Unix/Linux terminology, do child processes of a process include grandchild processes of the process?
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3answers
35k views

How can I see what processes are running?

I use Ubuntu Server 10.10 and I would like to see what processes are running. I know that PostgreSQL is running on my machine but I can not see it with the top or ps commands, so I assume that they ...
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1answer
1k views

long format of ps command in Solaris

Jobs with a long command-line is not printing in Solaris: bash-3.2$ /usr/ucb/ps auxwww | grep ftf | awk '{print $NF}' | head -5 /proj/cmp01/app/btws/cfg/btw /proj/cmp01/app/btws/cfg/btw ...
3
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1answer
582 views

What is meant by “Unknown instance” when restarting a service?

I am trying to get vsftpd file server running on Ubuntu 13.10, I'm unable to connect to the server from another network, although this other network is connected to the server's network and ping is ...
1
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1answer
42 views

How can I tell why a process is waiting?

I'm trying to run a command on OSX Mavericks and it seems to be hanging. I found out that Control + T is a Unix command to show the status of a foreground job. Pressing it several times over the ...
2
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1answer
211 views

Kill any service running at a specific port

I am trying to write a script that kills service running at a specific port. This is my script: a=$(ps ax | grep 4990 | grep java | awk '{print $1}') kill -9 $a It's a java program. This script ...
10
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1answer
7k views

How to suspend and resume processes like bash does

this question is a follow-up to: How to suspend and resume processes I have started firefox from a bash session in gnome-terminal. The process tree looks like this: $ ps -e -o pid,ppid,cmd -H 1828 ...
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3answers
47 views

How can i get the process with the biggest pid?

How can I get the process with the biggest pid using ps?
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2answers
195 views

Do all Linux processes write EOF to stdout when they are terminating/have finished terminating?

I'm having trouble with sending shutdown -h 0 to a lxc Debian container (i.e. executing this command in the lxc) with with the python pexpect module (in a python script). In this module the user can ...
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1answer
3k views

Modify 'Soft Limit' of 'Max processes'

I tried ulimit -u 2000 and ulimit -Su 2000 to modify the 'Max processes', and started up my program, but failed. I found file '/proc/pid/limit' is still: Max processes 1024 ...
2
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0answers
55 views

Cgroups - memory subsystem

I want to set the memory.limit_in_bytes parameter for a control group and disable OOM, so processes freeze when the limit is reached. But i want to change that limit dynamically, if there is more ...
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2answers
5k views

Who's got the other end of this unix socketpair?

I want to determine what process has the other end of a unix socket, that was created with socketpair(). I have a program parent which creates a socketpair(AF_UNIX, SOCK_STREAM, 0, fds), and fork()s. ...
0
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1answer
99 views

How to determine who started a process? [duplicate]

every few minutes I found this process running root 949062 100 0.0 37204 1488 ? R< 05:14 0:51 /usr/local/cpanel/3rdparty/bin/clamdscan --quiet --no-summary /etc/passwd It's ...
4
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1answer
153 views

Launch background processes in one group and later kill them all

The other day I tried writing a script that would kill a PID and all its children processes, but after spending some time on it, I decided it wasn't trustworthy, because sometimes some of the children ...
2
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1answer
260 views

Why is the PGID of my child processes not the PID of the parent?

So I keep reading everywhere that this command should terminate all child processes of the parent process: kill -- -$$ Using a negative ID with the kill command references a PGID and from the ...
3
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1answer
95 views

Monitoring filesystem activity

Say, I have a program, and I want to monitor its filesystem activity (what files/directories are created/modified/deleted etc.) This program may be capable of spawning further processes, and thus, I ...
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2answers
721 views

What is the need of the struct thread_info in locating struct task_struct?

While reading through the Linux Device Drivers, I could understand that the Process Descriptor (of type struct task_struct) has all the info regarding a particular task. The process descriptors are ...
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1answer
30 views

killall <processname> throughout the system [closed]

I'm opening two terminal windows. Terminal 1 - I run process1 Terminal 2 - I run process2 I then terminate both process using Ctrl+Z in each window. I type killall -9 process1 in Terminal 2 , ...
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3answers
425 views

detect process eating cpu without: top, htop, ps?

I went thru a problem where I could only guess what process was eating the cpu. My cpu usage was about 80% for all cores at psensor. I tried htop, top and ps -A -o pcpu,pid,cmd --sort +pcpu (the ...
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4answers
209 views

Single instance of script, but only with same arguments

I have this beautiful little code here that will exit from a script if there's another instance of it running: single_instance(){ if pidof -x "${0##*/}" -o %PPID >/dev/null; then exit ...
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2answers
84 views

CPU percentage of a single process

How do I get the average CPU percentage (for every second) consumed by a single process since it starts until it ends (exists)? Could I make this with Top?
5
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1answer
104 views

Why does `bash -c somecommand` sometimes not leave a bash process?

On an Ubuntu 12.04, with GNU bash, version 4.2.25(1)-release (x86_64-pc-linux-gnu), I tried the following command: $ bash -c 'pstree -s $$' init───sshd───sshd───sshd───bash───pstree $ bash -c 'pstree ...
10
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3answers
8k views

How to see how many context switches a process makes?

I want to see if my process makes a lot of context switches. I also want to see how manpulating task groups affects the number of context switches.
2
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0answers
47 views

CGroup Processes Not Terminated even when main process has been killed through Systemctl stop command

I am running systemctl stop process command for some process. Please find the output for systemctl status process below: Loaded: loaded Active: deactivating (stop-sigterm) CGroup: ...
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2answers
26 views

Meaning of PF_VCPU and PF_WQ_WORKER

do you know what the constants meaning is defined in linux/sched.h: #define PF_VCPU 0x00000010 /* I'm a virtual CPU */ #define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */ What ...
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2answers
61 views

Limiting number of processes by name

is it possible to limit number of processes for a given group or user using the process name? Eg. I'd like to groups remotes have only 5 simultaneous ssh processes that are run on my server. I don't ...
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1answer
13 views

how to suspend other nonrelated processes to allow a proces in interest to occupy the CPU?

Is it possible to first find out what processes are necessary to run a process in interest, and then suspend all other unrelated processes to allow the process in interest to use the CPU as much ...
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1answer
63 views

How are zombie processes handled when the parent dies?

Which technique does the Unix system use to remove zombie processes whose parent has terminated?
0
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1answer
437 views

How to figure out memory leaks? [closed]

I'm running Ubuntu 14.04 on Digitalocean to host my blog. I'm using HHVM + nginx + MySQL. Every few hours (~12h), there's no more RAM left and nginx throws an 502 error. I check the memory usage for ...
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1answer
78 views

Getting the parent path from a script

I have a bash script foocaller, which calls a ruby script foo: foocaller /path/to/foo Within foo, I want to get the path of foocaller. Following this suggestion, I put the following code to do ...
0
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1answer
44 views

get cpu by user

Working with monit I need create an alert that get cpu usage of system users, so: top -b -n 1 -u user1 | awk 'NR>7 { sum += $9; } END { print sum; }' seems a good solution but I'm not sure about ...
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1answer
2k views

The meaning of output of pmap

I wrote main.c in Linux: int main() { while (1){} } When I compile and start it, I can pmap it: # pmap 28578 28578: ./a.out 0000000000400000 4K r-x-- /root/a.out 0000000000600000 4K ...
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1answer
187 views

Understanding the difference between pid_max, ulimit -u and thread_max

I am trying to understand the Linux processes. I have confusion on the terms pid_max, ulimit -u and thread_max. What exactly is the difference between these terms? Can someone clarify me the ...
4
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3answers
181 views

how to determine how many times pid_max wrapped?

Is it even possible to know that? may be some kind of tests are required to be performed in order to find that information? My system, just after I login, seem to have already wrapped the max_pid, so ...
39
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4answers
3k views

Why do we need to fork to create new processes?

In Unix whenever we want to create a new process, we fork the current process, creating a new child process which is exactly the same as the parent process; then we do an exec system call to replace ...
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2answers
58 views

Get command PID and send to another [duplicate]

I wanted to know if I can execute a command from the terminal and right after the command started I send its PID to another command to be monitored. I need to do something like this, dd ...
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2answers
37 views

List of files accessed by application

I want to install propertiary AMD driver but I would also like to know which files were created/changed by installer. Is there some application which can observe (probably by inotify) which files were ...
1
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1answer
590 views

kill pid is not working? [duplicate]

This is pretty weird now. I am trying to kill a process by using its pid but it is not working at all. root@machineA:/home/david# ps aux | grep modelling david 5075 0.0 0.0 1285420 29404 ? ...
12
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2answers
1k views

How to terminate remotely called “tail -f” when connection is closed?

I just noticed that if I execute ssh user@remote_host tail -f /some/file , then tail -f /some/file keeps running on the remote_host even if ssh connection is closed! So, after several connects and ...
4
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1answer
78 views

What causes /proc/<pid>/* resources to become owned by root, despite the procs being launched as a normal user?

I've noticed that some procs, such as bash, have their entire /proc/<pid>/ resources readable by the user who created that proc. However other procs, such as chrome or gnome-keyring-daemon, have ...
3
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3answers
7k views

Fix “firefox is already running” issue in Linux

I am trying to open Firefox in CentOS, but I'm getting the following message: Firefox is already running but is not responding and Firefox doesn't open. I tried this in command line: kill ...
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4answers
124 views

How to set the process won't be terminated when the terminal stops

[Edit] Make it simple. I invoked java xxx... on Machine A using putty to connect from Machine B. However I cannot reach Machine B. How can I connect Machine A from Machine C to set the running ...
3
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5answers
793 views

Run a process to particular/dedicated pid only

I have a c program executable or shell script which I want to run very often. If I want to stop/pause or to notify something I will send signal to that process. So every time I have to check the pid ...