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

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5
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675 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 ...
4
votes
1answer
345 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
vote
1answer
41 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
votes
1answer
111 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 ...
13
votes
2answers
806 views

How to find out what process is writing to STDOUT?

I have two instances of a process running. One of them is "frEAkIng oUT!" and printing errors non stop to STDOUT. I want to kill the broken process but I have to make sure I don't terminate the wrong ...
1
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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?
0
votes
1answer
760 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 ...
2
votes
0answers
48 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 ...
1
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2answers
160 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 ...
0
votes
1answer
92 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 ...
2
votes
1answer
139 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 ...
4
votes
1answer
125 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 ...
3
votes
1answer
80 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 ...
1
vote
1answer
29 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 , ...
3
votes
2answers
71 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?
4
votes
4answers
206 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 ...
5
votes
1answer
101 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 ...
1
vote
3answers
270 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 ...
2
votes
0answers
41 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
vote
2answers
25 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 ...
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 ...
0
votes
1answer
376 views

How to compute Linux slab memory leak in GNU/Linux ( proc/slabinfo ) of running process

How to compute Linux slab memory leak in GNU/Linux ( proc/slabinfo ) of running process ? I'm want to free usage is not working properly . I want to way how to check Memory Usage & Memory Leak ...
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votes
1answer
51 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?
2
votes
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 ...
0
votes
1answer
330 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
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1answer
73 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
40 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 ...
1
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1answer
124 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
148 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 ...
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2answers
50 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 ...
38
votes
4answers
2k 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
1answer
351 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 ? ...
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votes
2answers
317 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 ...
12
votes
2answers
824 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
69 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 ...
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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 ...
1
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1answer
669 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
245 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 ...
1
vote
4answers
120 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 ...
1
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2answers
242 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
644 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
50 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 ...
3
votes
5answers
550 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 ...
3
votes
1answer
58 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
73 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 ...
2
votes
1answer
230 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 ...
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3answers
95 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
830 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
959 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? ...
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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 ...