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

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2
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1answer
355 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
votes
1answer
118 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 ...
5
votes
2answers
732 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 ...
1
vote
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 , ...
1
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3answers
520 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 ...
4
votes
4answers
213 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 ...
3
votes
2answers
96 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
votes
1answer
105 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 ...
2
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0answers
51 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: ...
1
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2answers
27 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 ...
2
votes
2answers
63 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 ...
1
vote
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 ...
-2
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1answer
67 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
votes
1answer
519 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 ...
1
vote
1answer
84 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
votes
1answer
47 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 ...
6
votes
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 ...
1
vote
1answer
229 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
votes
3answers
226 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
votes
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 ...
1
vote
2answers
61 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 ...
1
vote
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 ...
2
votes
1answer
756 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
votes
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
votes
1answer
83 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 ...
4
votes
3answers
8k 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
133 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
votes
5answers
956 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 ...
1
vote
1answer
1k views

Is it possible to get process group ID from /proc?

In "http://stackoverflow.com/questions/13038143/how-to-get-pids-in-one-process-group-in-linux-os" I see all answers mentioning ps and none mentioning /proc. "ps" seems to be not very portable ...
2
votes
1answer
399 views

Obtain user and kernel time of a running process?

Is there way to determine using standard Linux/Unix tools how much a process has spent in User mode and how much waiting for kernel? In other words, exactly the "user" and "sys" values that you get ...
3
votes
2answers
263 views

How do I know if acct is running? (The Linux user accounting system)

I have installed the acct package and it is running because I can see file activity in the log file. I know there is the command accton on to turn it on, but how do I determine that its running short ...
1
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2answers
412 views

How can I find the process ID of a command started in another terminal?

If I run sleep 30 in one PuTTY window, how can I find the process ID of the sleep command from another PuTTY window?
3
votes
4answers
975 views

Keeping a process running on server even SSH is closed [duplicate]

I am running long program on server, which is basically Jar file of java program. I want to keep this program running even if SSH terminal is closed, how I can keep this program running on server?
1
vote
1answer
78 views

getting pid of two last commands executed in background and do stuff

I wrote this bash: #!/bin/bash eval "(a command) &" pid1=$! eval "(while kill -0 $pid1; do .... ; done) &" #It creates file.txt after few seconds pid2=$! if [ -s ...
2
votes
1answer
340 views

WITHOUT using network command lines in linux, how to know list of open ports and the process that owns them?

I want to know which ports are used by which processes in embedded-linux. Since it is simple embedded-linux, there are no network command lines such as netstat, lsof. (only basic command lines such as ...
3
votes
1answer
61 views

Is each process considered a thread?

Is a Linux process considered a thread? For example, if I write a simple c program that calls pthread_create to create a new thread in main(), does that mean that I now have 2 threads, one for ...
0
votes
1answer
77 views

Process switch with clone() [closed]

I'm new for Linux. Now, I have to write a c program and use clone() to make process do things asynchronous. I've read the manual of clone(); however, I still don't know how to make it work ...
1
vote
3answers
98 views

How do I shutdown the system after a particular process exits

I am downloading some software; I can see the pid of the download process with top. Let's say it's 1001. How can I make it so that my computer shuts down after process 1001 exits?
21
votes
3answers
934 views

If processes inherit the parent's environment, why do we need export?

I read here that the purpose of export in a shell is to make the variable available to sub-processes started from the shell. However, I have also read here and here that "Processes inherit their ...
3
votes
5answers
1k views

Getting pid of bash script from itself

I have a bash script with doing lot of things called script.sh: #!/bin/bash #It #Is #Doing #Things Is there a way that I be able to get the proccess of script and then kill it after 5 minutes? ...
18
votes
3answers
20k views

How can I pause/resume rsync

How can I pause an rsync that's running? First time I did Ctrl+C to kill it and used the -P flag to run again. Is this prone to corrupt the current file transfer? Second time I simply put MacOS to ...
1
vote
0answers
30 views

daemon causes problem to the device [closed]

Currently I am working on one hardware device and we are calling it as a Unit (there are about 100 units). This Unit is built on Ubuntu 12.04. There is one daemon called dispaly_msg which is used ...
3
votes
3answers
334 views

Is there a way to make your process use less CPU?

I want my device to use less CPU to save battery. I have a program that uses a large amount of it. nice won't help as all it does is change scheduling when CPU is at %100, while I don't want it to get ...
33
votes
5answers
41k views

How to monitor CPU/memory usage of a single process?

I would like to monitor one process's memory / cpu usage in real time. Similar to top but targeted at only one process, preferably with a history graph of some sort.
0
votes
1answer
42 views

understand if a shell process is in background?

I keep an instance of mutt idling on a terminal, if it is on index or pager I want it to be able to receive a macro from an external process (AutoKey or xdotool etc..), but the external program need ...
6
votes
1answer
518 views

will the same pid be used after getting killed?

I had a file opened using vim editor. It was in a ssh session and since I had been idle for a long time, the session got closed and I had to establish the connection again. I opened the file again ...
0
votes
2answers
147 views

Bind one process to multiple ports?

I have a socket server running and listening for incoming connections on a non-admin port (i.e. > 1024). I would also like for this process to be able to handle another type of connection on a ...
2
votes
1answer
204 views

How to move process from one namespace to other?

This question is similar to my question about how to list namespaces. So in addtition, I'd like to know some information about moving processes from one namespace to other? E.g. I have processes of ...
0
votes
2answers
75 views

Use xdotool in a telnet session

I have to simulate key presses in a telnet session, and everything has to be invoked by a shell script. #!/bin/sh telnet 192.168.1.14 50000 xdotool type "404" However, once the telnet session ...
4
votes
4answers
216 views

“Virtual” shell, ie. jailing an user inside a process after the (SSH) login

The title might not say much about the issue at hand so let me get straight to the point. Let's assume I have a casual user who can log in to the system via SSH into a bash shell. I also have a PHP ...