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

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1answer
39 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
120 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
52 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
36 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 ...
5
votes
1answer
830 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
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1answer
45 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 ...
7
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1answer
102 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 ...
4
votes
3answers
105 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 ...
33
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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
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2answers
41 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
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2answers
33 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
68 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 ? ...
2
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1answer
130 views

Why does't stopping the nginx server kill the processes associated with it?

When I stop nginx like this on ubuntu 12.04, I get the following errors: $ sudo service nginx stop Stopping nginx: nginx. $sudo service nginx start Starting nginx: nginx: [emerg] bind() to 0.0.0.0:80 ...
11
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2answers
549 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
48 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
3k 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 ...
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 ...
3
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5answers
246 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
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1answer
126 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
120 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
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2answers
218 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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3answers
111 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
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4answers
301 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
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1answer
35 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
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1answer
128 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
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1answer
51 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
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1answer
65 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
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3answers
80 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
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3answers
739 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
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5answers
605 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? ...
17
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3answers
16k 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 ...
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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
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3answers
113 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 ...
27
votes
5answers
31k 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
36 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
435 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
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2answers
50 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
96 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
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2answers
35 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
206 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 ...
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 ...
0
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3answers
4k views

What is the difference between ps and top command?

What is the difference between ps and top command ? I see that both can display information about running processes . Which one should be used when ?
1
vote
1answer
129 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
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1answer
77 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 ...
5
votes
2answers
440 views

Suggestions needed to debug why ps -ef gets stuck

A few of my processes consume 100% cpu. I'm trying to figure out which scripts are causing it I tried running strace ps -ef: open("/proc/PID/status", O_RDONLY) = 6 read(6, "Name:\textract\nState:\tR ...
3
votes
1answer
68 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?
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2answers
426 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
votes
2answers
172 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 ...
3
votes
2answers
43 views

What does it mean exactly when a processes “Time” has stopped in top?

I'll be looking into why we're getting critical swap alerts, and I'll find something like: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ SWAP COMMAND 14683 user1 30 10 16.0g 772m ...
2
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0answers
26 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 ...