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

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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 ...
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Kill only one Java process

I usually run few Java applications, one for server running locally and other for some IDE like NetBeans. And from time to time, after lots of redeployments, my server get stuck on ...
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251 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 ...
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397 views

How to locate a Chrome tab from its process PID?

I opened many Chrome tabs for webpages. Each tab has its own PID, e.g. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND t 3900 1.9 6.3 5718440 508660 ? Sl ...
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9k views

What is a command line alternative to top for finding current CPU utilization that isn't dependent on screen width?

If I run top -p <myPID> -n 1 with a terminal that isn't wide enough, the CPU utilization % is omitted from the output. When trying to find a process' cpu utilization via bash scripting, this is ...
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2k views

Using top to see processes run by a user on behalf of sudo

If I run top -u username I will see all the processes by a particular user. Is there a way to also see all the processes that the user called via sudo?
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522 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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365 views

LD_PRELOAD or similar to prevent network access

I'd like to start a program disconnected from the network (because immediately upon starting it tries to download huge amounts of data, which can be prevented by changing settings as soon as it ...
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1k views

Is there a way to listen to process?

I want to know if there is a way to listen to a process in linux & unix - when it ends and what's the exit code of the process(script). I dont want to write a script that will run X seconds and ...
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105 views

Is it the process that cleans itself on termination or the kernel?

Recently I found this in a powerpoint presentation: When a program is compiled and linked, the linker inserts some extra code in the program. It is this code that calls the main function about the ...
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561 views

A way for saving running state of a program

I have a program that will perform a lengthy calculation which may take several days to be completed. Is there a way to save the program's running state; so I will be able to turn off the computer ...
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16k views

How to find Heap memory of a running process? [duplicate]

I would like to know how to find the heap memory of a process that is running in the background. Is there any command that allows such?
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How to get whole command line from a process?

How can I get the command arguments or the whole command line from a running process using its process name? For example this process: # ps PID USER TIME COMMAND 1452 root 0:00 ...
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863 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 ...
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1k views

Where is the virtual memory stored on hard drive?

If a process wants to access a memory address that is not in physical memory, the OS outsources a page frame from physical memory to the hard drive for later use. Where on the hard drive is this data ...
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6k views

kill a group of processes with negative PID

kill -TERM -PID is supposed to kill PID and all its child processes. but this doesn't work on openSUSE, it always tell me that no such process -PID no matter what PID i use. So if the negative PID ...
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733 views

Why is there a type for process ids (pid_t), but not for file descriptors (fd)?

I see that pid_t is typedef'd in unistd.h, and file descriptors are defined to be int in fcntl.h. But since they are used in similar ways, wouldn't it make sense to have a typedef for file ...
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1k views

What's the best way to determine the working directory for UNIX process using 'ps'?

I am running a Ruby command line script (rufus.sh)which ultimately calls Thread.new, which spawns a UNIX process as shown below. I run this script for more than 1 directory as the output of the ps ...
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211 views

My /var/log/ is mysteriously filling up GBs in minutes! Any cure before I re-install Debian 7?

Good morning, fellow *nix enthusiasts! I have been using Debian 7 for a while now and after a recent upgrade I noticed I constantly kept running out space on my root partition. I mean to the point ...
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2k views

How to kill a process started as daemon?

I start a process using foo &. It outputs something like: [1] 16915 This is the process id, I guess. How can I store this number into a variable named MY_PROCESS_ID (for example)? Then I ...
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650 views

Locate a directory from a relative path in ps output

When I executed the command to give the pid of my processes running, it gave me like this - user@machineA:/$ ps -eo pid,command | grep exhibitor | grep java | grep -v grep 1615 java -jar ...
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865 views

What is the difference between exiting a process via Ctrl+C vs issuing a kill -9 command?

I know I can kill any process with kill -9 command . But sometimes i see that even if I have terminated a program with CTRL+C , the process doesn't get killed . So I want to know the difference ...
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154 views

Zombies in bash

Bash doesn't seem to create zombies. It looks like the processes get immediately reaped when they get killed. Can I make bash make zombies? Why I'm asking: I'd like to be able to safely kill a ...
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83 views

How to kill a bunch of jobs based on ps output?

Here is output from ps: $ ps aux | grep blob ubuntu 4286 0.0 0.1 34748 9592 ? S Jan14 0:00 /usr/bin/python /usr/local/bin/pynt start_blob_reader ubuntu 4287 0.0 0.1 34748 ...
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138 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.
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How to view a specific process in top

Are there any relatively strightforward options with top to track a specific process? Ideally by identifying the process by a human readable value? e.g. chrome or java. In other words, I want to view ...
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How can process doing “vfork without exec” end up in a long uninterruptible sleep?

In this answer user suggests that Normally, Uninterruptible sleep should not last long, but as under windows, broken drivers or broken userpace programs (vfork without exec) can end up sleeping ...
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Preserve evidence of intrusion / deleted executable?

If you are faced with a non-root remote command execution vulnerability, and there is a foreign executable that's running on your Linux system from a user with only non-administrator privileges, ...
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10k views

I can't install new packages and can't update and upgrade

I'm trying to install some program on Ubuntu, but when I try it I got the following error.- E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock ...
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316 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 ...
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Why is `sudo pkill -HUP -f “nginx: master process”` returning code 129 and no output

I'm trying to trigger a reload of the Nginx master process by using pkill and sudo. The server reloads fine, but I was just curious if anyone knows why the command sudo pkill -HUP -f "nginx: master ...
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Linux running slow with 0 swap left

Our Linux server is responding very slowly. top doesn't show any excessive CPU usage. I noticed that even though there's about 5GB of free memory, the system is using all of swap with no free swap ...
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Fork bomb on a Mac?

I just learned about a fork bomb, an interesting type of a denial of service attack. Wikipedia (and a few other places) suggest using :(){ :|:& };: on UNIX machines to fork the process an infine ...
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915 views

Removing zombie process from the process table

Can somebody please explain when parent process receives the exit status of a dead child process via wait, who actually reallocates the memory of the child process and removes it from the process ...
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retrieving names of all open pdf files (in evince or otherwise)

I constantly have many PDF files open. These are usually downloaded using chrome and immediately opened using evince. I sometimes want to persist the state of all my open PDF files, so I could ...
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79 views

CPU usage of file system operations not shown in top

I run the following command (which does ls for 10,000 times) in a Ubuntu Linux terminal and use the top command to monitor the CPU usage. While top shows the total CPU usage (line 2) is about 48% ...
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htop shows only the processes of the user that's running it?

On my old Debian Wheezy I see as a normal user without sudo all processes from all user in htop. On my new Debian Wheezy I only see my own processes. Old system kernel: 3.2.0-4 New system kernel: ...
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Determining maximum memory usage for an extremely short process

I have a program I am testing and I need to determine the maximum memory used by the process. I know that in general ps -aux can give me this information, but the process runs in under 1/10 seconds ...
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650 views

How do I find the resident memory size of a process on busybox?

I run top on busybox and it shows all processes and their virtual memory size. How do I determine how much RAM is being used by each process?
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Maximum memory usable by a 32 bit RHEL 6 system

I have installed a 32 bit RHEL OS on a 64 bit system. From the wiki page of PAE: The Linux kernel includes full PAE mode support starting with version 2.3.23, with Linus Torvalds mentioning ...
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54 views

Suspend and edit previous single line commands

Say I want to modify the latter of some concatenated command line options, is it possible without killing the first command? Specifically I have compile and run scripts executed thusly: > compile ...
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477 views

How to know which commands are executed when I do something in GUI

This is for academic purpose. I want to know which commands are executed when we do something in GUI, for example creating a folder. I want to show that both the mkdir shell command and create folder ...
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138 views

Get process list with logical intersection of selectors?

The Linux ps command allows multiple selectors, such as user and command name, but always returns the logical OR of those selectors (more than I want). Does anyone know of a method or tool already ...
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How does forking affect a process's memory layout?

Please see the following figure showing the memory layout of a process: : When someone forks(), and a new task_struct is assigned, what happens to the addresses of the process? In more or less other ...
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828 views

controlling a process from a different session

So, I ssh into my remote computer and launch a process... time passes... my ssh session breaks. I log in again, and of course, I don't have access to the original process now. I can see it still if I ...
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262 views

start process so that it can't spawn new ones

Is it possible to start new process so that it couldn't spawn new ones (untrusted code)? Also how do I start a process so it couldn't make any input/output to files and in general any devices?
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423 views

Kill process when it stops to produce further output

Is there a shell tool which can probe if a subprocess is still producing output, and otherwise kill it after a specified timeout? I'm using offlineimap for Gmail backup, but that's very very very ...
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884 views

Difference between process group and job?

What's the difference between a process group and a job? If I type pr * | lpr then is it both a process group as well a job? What exactly is the difference between a process group ID and a job ID? ...
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51 views

What is /proc/<pid>/net/dev?

I'm interested in per-process network I/O counters, like those in /proc/net/dev and found what I thought was it under /proc/<pid>, i.e. /proc/<pid>/net/dev. But it seems that was too easy ...
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909 views

Alternative to iotop for non-root user without sudo privileges

I'm looking for an alternative to iotop. Here's my situation: I want to find out if a program is accessing the hard drive a lot while running. iotop requires root/sudo privileges. My account is on ...