A process is an instance of a computer program that is being executed.
4
votes
5answers
108 views
Is a persistent zombie process sign of a bug?
(OS: Debian variant.)
Having a process with zombie-status. The PPid belonged to a gvim process.
The contents of /proc/[pid]/wchan is do_exit,
/comm is sh and /cmdline is empty, /status is shown ...
7
votes
1answer
2k views
How to suspend and resume proccesses like bash does
this question is a follow-up to: How to suspend and resume proccesses
I have started firefox from a bash session in gnome-terminal.
The proccess tree looks like this:
$ ps -e -o pid,ppid,cmd -H
...
6
votes
2answers
467 views
Viewing foreground process using ps
I can see the background process using ps. But Is there a way to view the foreground process? For example,
$nohup process1 &
then
ps -ef | grep "process1"
would display the process ...
-1
votes
1answer
19 views
How to check the ports of Main and dependent Programs [closed]
we can see the ports using the Netstat -tulpn, e.g netstat -tulpn |grep program.
But what is there is program that has multiple modules dependent on main program. How we will know what ports are they ...
3
votes
3answers
2k views
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 ...
3
votes
3answers
41 views
How can you change the process name of Wing IDE from python to something more descriptive
In my process list under Ubuntu (using top/System Monitor) one of the largest memory hogs (200+Mb) was python. I searched a bit for one of my programs to be the cause until I realised this was my ...
2
votes
1answer
236 views
How to find Heap memory of a running process? [duplicate]
I would Like to know how to find the heap captured of a process which is running in the background?
Is there any command by which you can find the process heap memory and here the process is still ...
2
votes
1answer
68 views
How to demonstrate invalid PID assumptions?
It seems many programmers are happy with saving a PID to a file, and then later read and use the PID as if it was guaranteed to be the same process. It seems the general idea is that the odds are good ...
1
vote
1answer
71 views
Do kernel counters for jiffies in state exist in Linux?
I am looking to get time/jiffie stats on the state of a daemon process. The states I'm referring to are mentioned in the Linux Kernel Proc Filesystem document. Running, Sleeping, uninterruptible ...
2
votes
3answers
137 views
How do I start a process with a nice value of -20 and not give it root privilege?
I would like to start a process with a nice value of -20. This requires me to use a command like - sudo nice -n -20 matlab. However, this starts matlab as root too. Is there a way to have matlab as ...
0
votes
0answers
29 views
Pass process ownership to another shell [duplicate]
I didn't hear of anything like this, but It might be possible.
I often end up starting a process on a server and midway realizing that I would like to suspend that process and continue it inside a ...
1
vote
1answer
45 views
Looking for /procfs documentation, describing values and units of measurement
Surprisingly, comprehensive documentation for /procfs is hard to find.
For my specific question, I am looking at: cat /proc/1/statm (let's use pid=1 because it seems to be always there). I just ran ...
1
vote
2answers
48 views
Tracking which files are used by program
I am looking for a way to track which files are used by program installer(InstallAnywhere). I cannot use lsof because as far as I know it works on active processes and I want a tool which will work ...
1
vote
2answers
78 views
How to decrease ps aux output to a few lines?
When my computer is slowing down, I usually run ps aux --sort -rss to find out which process consumes too much memory. There may be a lot of processes. How to see only a few ones?
0
votes
1answer
69 views
Move terminal emulator process from xorg to tty? [duplicate]
Is it possible (and if so, how?) to move a process from a terminal emulator running in X to a different virtual terminal, so that I can restart the X server without killing the process running in the ...
0
votes
4answers
169 views
Show running processes with file name(s)?
I am using putty to connect my linux server which my sites are in. I can run
# ps aux | less
to show running processes. But I want to display which files running these processes ?
I have also ...
3
votes
1answer
660 views
A tee >( process ) is truncating its stdout when writing a file
When I use tee to pipe stdout directly to a "specific block of code" (which then writes the modified data to a file), I always get the full complement of exptected output lines in the file.
...
2
votes
2answers
72 views
End process from another SSH window
I forgot to use screen and I have a task that has been running for quite some time, and I do not want to lose the saved data. Basically Ctrlc will end the task and save the data if I am on the same ...
11
votes
2answers
469 views
Why does bash show 'Terminated' after killing a process?
Here is the behaviour I want to understand:
$ ps
PID TTY TIME CMD
392 ttys000 0:00.20 -bash
4268 ttys000 0:00.00 xargs
$ kill 4268
$ ps
PID TTY TIME CMD
392 ttys000 ...
4
votes
3answers
265 views
Silently start task in background
I know that you can use this to start a process in the background, without getting the notification when the process is put in the background and when it is done like so:
(command &) &> /dev/null
...
1
vote
3answers
164 views
Block network access of a process?
Is it possible to block the (outgoing) network access of a single process?
6
votes
3answers
2k views
How to read environment variables of a process
Linux's /proc/<pid>/environ does not update (as I understand it, the file contain the initial environment of the process).
How can I read a process's current environment?
81
votes
11answers
36k views
What if 'kill -9' does not work?
I have a process I can't kill with kill -9 <pid>. What's the problem in such a case, especially since I am the owner of that process. I thought nothing could evade that kill option.
2
votes
2answers
106 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 ...
2
votes
1answer
274 views
What does kill 0 do actually?
In the man page, it says:
kill [ -s signal | -p ] [ -a ] [ -- ] pid ...
pid... Specify the list of processes that kill should signal. Each pid can be one of five things:
0 All ...
6
votes
1answer
149 views
What should interactive shells do in orphaned process groups?
(Re-posting in unix per the suggestion in http://stackoverflow.com/questions/13718394/what-should-interactive-shells-do-in-orphaned-process-groups)
The short question is, what should a shell do if it ...
3
votes
1answer
394 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?
...
2
votes
4answers
228 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 ...
1
vote
2answers
96 views
How to know if a background job is finished?
I invoke a script (do_something) in background via another script (do_manythings) as below.
nohup do_something &
How would I know in the parent script (do_manythings) that the job invoked ...
1
vote
2answers
89 views
Invoke a command/script disconnected from the controlling terminal?
I'm investigating the behaviour of a script that is normally run as an automated process (e.g. cron, Jenkins). The script can (eventually) invoke commands that behave differently (seeking user input) ...
1
vote
1answer
65 views
What rules govern the parent-child relationship of processes launched by shell across a pipe?
#!/bin/ksh
# start_service: start the service
my_server_executable 2>&1 | my_pipe_following_shell_script &
exit 0
After I run the above start_service script from command line, it is ...
11
votes
4answers
296 views
Is there a top-like command that shows the network bandwidths and file accesses of running processes
For example, we'd like to see:
PROCESS IF TX RX FILE(regular) R/W
prog1 eth0 200kB/s 12kB/s -- --
wlan0 12kB/s 100kB/s -- ...
41
votes
3answers
17k views
How do I read from /proc/$pid/mem under Linux?
The Linux proc(5) man page tells me that /proc/$pid/mem “can be used to access the pages of a process's memory”. But a straightforward attempt to use it only gives me
$ cat /proc/$$/mem ...
3
votes
3answers
204 views
What after exec() in ls command. Is the parent process printing the output to the console or the child?
I have a simple doubt on execution of the command ls. As per my understanding from the research I have done on the internet, I understood the below points.
When we type ls command shell interprets ...
2
votes
4answers
4k 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 ...
3
votes
0answers
97 views
Elegantly get list of descendant processes
I would like to get a list of all the processes that descend (e.g. children, grand-children, etc) from $pid. This is the simplest way I've come up with:
pstree -p $pid | tr "\n" " " |sed "s/[^0-9]/ ...
2
votes
1answer
344 views
Linux : See CPU usage by a process for the last second
vmstat 1
Above will print virtual memory statistics each seconds. It will also show the CPU utilization for last second.
I have a web server at hand which runs httpd and MySQL. I need to find how ...
4
votes
1answer
142 views
Elegantly get list of children processes
I would like to get a list of all the processes whose parent is $pid. This is the simplest way I've come up with:
pstree -p $pid | tr "\n" " " |sed "s/[^0-9]/ /g" |sed "s/\s\s*/ /g"
Is there any ...
1
vote
2answers
211 views
multiple background processes in a script
Suppose if i have a situation in which some files need to be copied and it takes long time so
i would have to go for parallel processing of the file copy.
for example it may look like this
for i in ...
3
votes
1answer
197 views
Cannot kill a java process
I have a java process that cannot be killed. I have tried every method I know, or that I have found on the internet to no avail. I have tried:
killall java
kill -9 <pid>
kill -11 <pid>
...
3
votes
3answers
224 views
Running multiple nohup commands in background
Got two commands cmd1 and cmd2. Of the two, cmd2 takes longer to finish. Need to run cmd2 and then cmd1.
Tried to run them in following way:
bash$ (nohup ./cmd2>result2 &) && nohup ...
0
votes
2answers
74 views
Which process updates /proc/scsi/scsi?
I wrote C that displays info about my hardware on ubuntu. Now I wonder how I can make it more flexible such as querying the hardware directly instead of the file the os updates. So I think I can look ...
13
votes
3answers
1k views
How to kill a process with a single command?
I want to kill a process, after finding the id in a single step.
I currently use these two commands:
pidof <name>
kill <#number_which_is_result_of_command>
How can I write a single ...
17
votes
1answer
518 views
How does systemd survive a kill -9?
Between the recent "Why does 'kill -9 0' end my console session" and "How to get a kernel panic" questions, I got a bur under my saddle and tried kill -9 1 on a mostly up-to-date Arch linux laptop. I ...
2
votes
2answers
70 views
what happens when a window manager is put to background
I am trying to understand the situation why .xsession file expects the last process to be in foreground otherwise it is supposed to stop X11 session.
I have a small stand-alone script. when I run ...
7
votes
5answers
2k views
Under AIX, how can I get the full path of a program bound to a port?
Under Linux I can use netstat -tulpnw and ps, like so:
# netstat -tulpnw | grep :53
tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN 1482/named
udp ...
6
votes
1answer
259 views
Why does “kill -9 0” end my console session?
I just wonder why kill -9 0 ends my tty console session?
What exactly is PID 0, it is not listed on a ps aux?
2
votes
4answers
93 views
Capture complete process structure/stack
There are a lot of java processes running on the server, generally, we capture the PIDs of the java processes using command 'ps -ef | grep java'. In general, the java processes have a lot of jars in ...
14
votes
2answers
454 views
How are the processes in UNIX numbered?
I can't find any pattern when I look at the numbering of PIDs in process table (ps -a), as the PIDs are not subsequent numbers and sometimes there are large "gaps" between those numbers.
Is it ...
-3
votes
2answers
67 views
Which Linux distro/mode offers lowest interference when running your own applications?
I'm interested in a Linux distro to build C projects and test their behavior in a very predictable and controlled environment. I'm especially concerned about letting the scheduler deal as much as ...
