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

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5
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495 views

Dynamic file content generation: Satisfying a 'file open' by a 'process execution'

I have a read-only file, F. A program, P, that I'm not the author of, needs to read F. I want the content of F to come from another 'generator' program, G, whenever P tries to read F (taking F to ...
1
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1answer
556 views

How can I kill child processes with start-stop-daemon?

I'm writing a simple web server using nc and bash. It looks like this: #!/bin/bash rm -f /var/run/streamman/out mkfifo /var/run/streamman/out trap "rm -f /var/run/streamman/out" EXIT while true do ...
2
votes
1answer
1k views

How is it that I can attach strace to a process that isn't in the output of ps?

I'm trying to debug why our integration tests are taking so long and it looks like they're hanging part way through. I logged onto our test service and saw the following behaviour: root@colossus:~# ...
1
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0answers
50 views

How can I find which process is eating my memory? [duplicate]

My Linux system sometimes reaches 90% memory usage. We are running some Java processes, and top shows overall usage as 45%. If I stop the running processes, usage reduces to 5-10%. I want to list ...
2
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1answer
25 views

Re-enter PID 1 namespace

I'm trying to enter PID namespace that process with PID 1 is in from a process cloned with CLONE_NEWPID. I keep getting Invalid argument error. In other words, I clone a child process with clone() ...
25
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9answers
2k views

How can I kill a process and be sure the PID hasn't been reused

Suppose, for example, you have a shell script similar to: longrunningthing & p=$! echo Killing longrunningthing on PID $p in 24 hours sleep 86400 echo Time up! kill $p Should do the trick, ...
2
votes
1answer
26 views

Solaris 10 system - used disc space keeps on increasing even after deleting the directory

I deleted a directory on slice mmf but it came back - the size is still same and also it keeps increasing. The reason for deleting the directory is that I couldn't find the process linked to creating ...
2
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1answer
27 views

Is there a way to suspend an process belongs to shell A and foreground it in shell B?

I knew how to suspend one process and bring it into foreground in current shell, but I have no idea about that If I have run a process in shell A and now I want to bring it into foreground in current ...
28
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5answers
9k views

Measuring RAM usage of a program

time is a brilliant command if you want to figure out how much CPU time a given command takes. I am looking for something similar that can measure the max RAM usage of the program and any children. ...
1
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1answer
56 views

Difference between owner/root and RUID/EUID

I am relatively new to the concepts mentioned in the question and reading about them from different sources only makes them more confusing. So this is what I understood so far: When we are given ...
2
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3answers
150 views

How can I determine if a process is a system process?

I'm reading the /proc directory (or pseudo-fs) to find all processes. I'm getting the information I need from /proc/[pid]/status but there's something else I need. Is there any way to figure out which ...
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0answers
17 views

Find what process implements a FUSE filesystem

How can I get the process ID of the driver of a FUSE filesystem? For example, I currently have two SSHFS filesystems mounted on a Linux machine: $ grep sshfs /proc/mounts host:dir1 ...
19
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5answers
7k views

Is there a program that can send me a notification e-mail when a process finishes?

I am a computational scientist, and I run a lot of lengthy calculations on Linux. Specifically, I run molecular dynamics (MD) simulations using the GROMACS package. These simulations can take days ...
9
votes
3answers
21k views

How to list processes locking file?

Using flock, several processes can have a shared lock at the same time, or be waiting to acquire a write lock. How do I get a list of these processes? That is, for a given file X, ideally to find the ...
11
votes
2answers
4k views

How do I tell a script to wait for a process to start accepting requests on a port?

I need a command that will wait for a process to start accepting requests on a specific port. Is there something in linux that does that? while (checkAlive -host localhost -port 13000 == false) ...
1
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2answers
44 views

Should I use Linux's acct (BSD process accounting) to track a process behavior?

I have a daemon process (slapd) which sometimes stops with no apparent reason. No segfault occurs. Nothing special in the logs. So, I'm trying to use acct to track the process' life, especially its ...
8
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3answers
2k views

Process descendants

I'm trying to build a process container. The container will trigger other programs. For example - a bash script that launches running background tasks with '&' usage. The important feature I'm ...
5
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3answers
9k views

Bash script wait for processes and get return code

I am trying to create a script which will start many background command. For each background command I need to get the return code. I have been trying the following script : #!/bin/bash set -x ...
0
votes
1answer
29 views

writing a script & trying to kill a process

So I am very new to Unix, I understand this question may be very simple My goal is to write a script that will show all the running processes and ask the user if they want to kill each process... For ...
3
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5answers
97 views

Get PID of process started by time

Say I run time ./a.out, then I can get the PID of time by the variable $!. But how do I get the PID of a.out? Of course, I could parse the output of ps, but I want a more elegant solution. I've ...
5
votes
3answers
413 views

Which of the following codes will run in the same process of the current shell

A. { echo "Hello World"; } >outputfile B. ( echo "Hello World" ) >outputfile C. ./anothershell.sh D. /bin/echo "Hello World" Which is right? And what kind of command can run in the same ...
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0answers
220 views

Does jps lie? If not, what else is this?

I am running dockerized hadoop cdh 4.6.0 with supervisor . I have opened the docker container and tried the following two commands. Got confused a lot. jps 103 -- process information unavailable ...
5
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4answers
387 views

list graphical processes from terminal

Do no confuse the question here with how to list processes graphically, that is not what I am asking. In the Terminal, how can i see which processes have a GUI? as in things like firefox, vlc, ...
3
votes
2answers
216 views

How to close a window of a crashed application?

Im using Awesome as desktop environment, as you can see in the image below, the application (aMule) crashed but the window is still open, so I would like to close it to restart it, but as you can see ...
0
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1answer
91 views

/usr/bin/awk: Argument list too long

I am trying to run the following bash script: #!/bin/bash file=$1 filename=${file%%.*} line1=$(sed -n 1~2p ${file}) seqs=$(grep -v '^>' ${file}) pos=$(echo "${line1}" | awk -F"[__]" ...
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0answers
16 views

Perform task on waking up from suspend

I have program that misbehaves when my pc wakes up from suspend to ram, it starts using up to 40% of processor time so i usually have to kill it manually. How can i set specific command (pkill in ...
2
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1answer
53 views

monitor multiple pids with top

I want to monitor memory usage for several processes and came up with a command like this: ps aux |grep -e postgres -e unicorn -e nginx|cut -d' ' -f2|for i in $(xargs); do echo $i; done 16112 16113 ...
0
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2answers
33 views

How to open process again? [duplicate]

From my home pc using putty, I ssh'ed into a remote server, and I ran a python program that takes hours to complete, and as it runs it prints stuff. Now after a while, my internet disconnected, and I ...
2
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3answers
78 views

Can you make a process pool with shell scripts?

Say I have a great number of jobs (dozens or hundreds) that need doing, but they're CPU intensive and only a few can be run at once. Is there an easy way to run X jobs at once and start a new one ...
0
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2answers
52 views

Meaning of the pstree output

-bash-3.2$ pstree 27108 Script.sh---java---15*[{java}] What does this 15* mean here, also any meanings defined for [] & {} in the context of command?
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1answer
26 views

How to find process which flood the whole network

I have a laptop with Fedora 21 and TP-Link router with DD-WRT software. Sometimes my whole internet stops for any device. When I reboot my laptop or just I turn off wireless, the internet works fine. ...
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1answer
79 views

shell script to auto kill processes matching certain criteria

when running top it shows a couple of processes got nearly 100% cpu usage of the command 'perl' PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 21287 simon 15 0 4141 ...
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0answers
47 views

process blocked in msgrcv

I have a process that is blocked in msgrcv as shown by ps -eo pid,tid,wchan. Is there any way to find the PID of the process that my process is expecting to receive a message from? The communication ...
0
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1answer
46 views

how to get list of all processes accessing a shared library [duplicate]

I know that ldd utility can list all libraries linked to a process but I want it the other way around. I want all processes linked to a library. I want to replace a shared library without crashing the ...
4
votes
3answers
105 views

How to not show the stdout output of a running process?

When a running process gives lots of stdout output throughout its lengthy running process, you don't want to kill it and rerun it. How can you not show the output? Thanks.
3
votes
1answer
37 views

Minus and Plus Sign in jobs Process

These commands are running in the background: foo@contoso ~ $ sleep 30 & foo@contoso ~ $ sleep 60 & foo@contoso ~ $ sleep 90 & What is the minus and plus sign after running jobs process? ...
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4answers
5k views

monitoring file changes + process access to files

I would like to see what's happening in my app server folders, which files are changed by process x or which *.war files has been changed (replaced/created) in last x minutes. I am software developer ...
2
votes
1answer
38 views

What's the easiest way to detect what signals are being sent to a process?

I'm trying to debug an issue with my shell (specifically, fish) sending signals to my background processes. I'd like to be able to recognize what signals a process is receiving. Ideally, I'd like ...
0
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2answers
53 views

Why can't I kill the shell using the PID obtained from the $$ special variable? [duplicate]

After I have learned that the $$ special variable holds the process number of the shell, I tried too kill the shell by simply: kill , however this did not work, I also tried some variations, but them ...
0
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0answers
48 views

Send a remote job to a remote server (second machine) and end the first process

I Installed ScanBD for my scanner on a RaspberryPi. I also wrote a script to process the files once the scanning function has completed. SCANBD Script SCANBD Process Script Currently, the scans are ...
2
votes
1answer
37 views

Creating symlinks in the etc directory without root access

What I would like to create if I had root access would be a symlink from some file or folder in the /etc to another file or folder in the /etc. However, I do not have root access. Is there any way to ...
2
votes
3answers
54 views

Controlling the environ passed to child process by bash

I am using x86_64 GNU/Linux with bash #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { system("set > setc"); // A subset of `$ ...
0
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1answer
65 views

How is user space process/thread controlled by the operating system

I understand this: User code executes in a process/thread context in a process address space, in user mode, and can address only user code/data defined for the process, with no access to privileged ...
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3answers
68 views

Can a suspended process be copied?

If I suspend a running job in bash using ctrl-z is there a way to copy it. So that I now have two processes that are the same. I am running a python script that loads several files and does some ...
6
votes
9answers
16k views

Bash way to check if a process is already running in the background (and skip re-execution based on that)?

Can I make a bash command line that only runs a certain command if the process is not already running (in the background)? How do I check*, if a command is already running? (so I can add the next ...
98
votes
7answers
64k views

How can I close a terminal without killing the command running in it?

Sometimes I want to start a process and forget about it. If I start it from the command line, like this: redshift I can't close the terminal, or it will kill the process. Can I run a command in ...
27
votes
6answers
46k views

Determining what process is bound to a port

I know that using the command: lsof -i TCP (or some variant of parameters with lsof) I can determine which process is bound to a particular port. This is useful say if I'm trying to start ...
77
votes
4answers
2k views

Can I somehow add a “&& prog2” to an already running prog1?

Most shells provide functions like && and ; to chain the execution of commands in certain ways. But what if a command is already running, can I still somehow add another command to be executed ...
3
votes
1answer
32 views

Parent restarted by child doesn't respond to CTRL-C

I wrote a program. It starts a process (call it A) that spawns a child process (call it D) that shutdowns and restarts A. Problem is, now I can't kill A nicely from the terminal (ie. CTRL-C isn't ...
2
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1answer
141 views

Why can't I kill this process?

Problem I would like to kill a process called raspivid (program which records videos using a Raspberry Pi Camera) but I cannot... This is how I call it: #!/bin/bash #Start recording... raspivid -w ...