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

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4
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4answers
189 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
78 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
106 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
24 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
24 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
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1answer
11 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
173 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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1answer
42 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
55 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
163 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
59 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
39 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
vote
1answer
58 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
115 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 ...
1
vote
2answers
45 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 ...
35
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
97 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 ? ...
7
votes
1answer
136 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 ...
11
votes
2answers
592 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
60 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 ...
1
vote
2answers
34 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
vote
1answer
208 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
148 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
107 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 ...
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3answers
133 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
375 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
40 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
284 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
55 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
68 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
157 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
85 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
760 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
666 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
24 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 ...
2
votes
3answers
156 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 ...
0
votes
1answer
38 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 ...
5
votes
1answer
448 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
57 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 ...
0
votes
2answers
40 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 ...
5
votes
5answers
1k views

Threads vs (Forked) Processes

Linux applications generally fork then exec (with execve() ), but Java applications, and certain Apache MPMs use threading. If forking, uses the fork + exec to spawn a process, what is the high level ...
1
vote
1answer
191 views

How to configure the process open file limit of a user?

The default open file limit per process is 1024 on - say - Linux. For certain daemons this is not enough. Thus, the question: How to change the open file limit for a specific user?
2
votes
1answer
82 views

“Kill the biggest process” button

This laptop has an SSD and therefore I decided to omit the swap. This works well in most cases, but sometimes the RAM gets a bit short and the computer gets really sluggish and tends to freeze up. Is ...
3
votes
1answer
81 views

How can I get the wall clock time of a running process?

I started a hash check of a large file and don't want to restart it using time. How can I get the wall clock time without using time at the beginning or using date right before I invoke a command?
2
votes
2answers
327 views

High Idle CPU / Low CPU Load average

After removing APC (alternative php cache), I noticed that there are less pagination access and less dirty pages but in the same time: High idle CPU Very low CPU load (relatively to the time before ...
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votes
2answers
564 views

Strange processes: “pro” and “proh” and slow Internet

I have two processes that start automatically and when that happens the internet speed decrease considerably. I tried to killed those processes but they start again, I tried to delete the executables ...
2
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0answers
32 views

Getting non-stored password from Icedove

I've recently changed my mail password (because of Heartbleed), but I've forgotten the new one. When entering the new password in Icedove, I didn't think of clicking "remember password", but the ...
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0answers
80 views

Measuring context switches of a LWP gives incorrect results. Why?

I have a Java thread pinned at my cpu core. It is busy spinning and I see through top that it is running fine: %Cpu0 : 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu1 : ...
2
votes
1answer
44 views

determine what service is running a script

I share a dev server with some colleagues, it's a Ubuntu server and we have several scripts there, so basically the usual way we run a process is using a screen session. My problem is that when I do ...
0
votes
1answer
161 views

Directory locked! [closed]

I have been trying to install virtualbox using this command: sudo apt-get install virtualbox.qt But I am getting this error: E: Unable to lock directory /var/cache/apt/archives/ I have been ...