All Questions
54 questions
12
votes
5
answers
13k
views
Why a fork is often followed by an exec?
Why "a fork is often followed by an exec"?
Can't you just create a new process in UNIX?
- 231
0
votes
1
answer
231
views
See htop tree evolve in slow-motion
Using htop and its tree view (trigger by t or F5) one can see processes by parenthood, and layout the relations between them as a tree.
Is there a way to see how the process tree evolves in slow ...
- 103
1
vote
0
answers
376
views
what does 0 link means in bash file descriptor?
Each process uses a set of open files in linux . Now bash ( a shell ) is also a process which uses different file descriptor for standard input output.
If I find some file descriptors :
ls -l /proc/$$/...
- 29
0
votes
0
answers
273
views
How to detect which process accesses a file?
I'm trying to reword this question: Is it possible to monitor which process accesses a given file/directory (on a Linux system)?
Background: on a regular basis I'm detecting file access to a certain ...
- 1,139
2
votes
0
answers
1k
views
Multiple Processes listening on Port 22? How is this possible?
I have a Solaris 10 Server that has SSH enabled, I wanted to find out which specific process is responsible for opening the socket that listens for the port 22. I used the PFiles utility to loop over ...
- 21
0
votes
0
answers
234
views
Why Solaris Message Queue Getting Full?
I am using below Solaris operating system -
uname -a
SunOS dcapp 5.11 11.3 sun4v sparc sun4v.
I have created 3 message queues here. Suppose message queue names are
AAA ( process a)
BBB ( process ...
0
votes
1
answer
71
views
How to scan/log already running processes on Unix
you can use ps to list running processes, but I would like to know if there is a way to inspect the running processes to any level of detail. for example, maybe there is a way to see every assembly ...
- 115
0
votes
1
answer
2k
views
Why Unix child processes inherit [most] parent process attributes
Learning about how Unix processes work, and noticed that child processes inherit most of the attributes (including file descriptors) from the parent process. I also just learned about exec and how it ...
user39251
-2
votes
1
answer
2k
views
What is the difference between a Service and a Process? [duplicate]
From a unix admin standpoint what is the difference please between those terminologies : Service, Process, Thread, Task, Job, Daemon ?
- 107
13
votes
3
answers
7k
views
How to find ancestor chain of a process?
I can do ps -o "pid,ppid,args" -p my_pid to find the parent of my_pid.
I can continue ps -o "pid,ppid,args" -p previously_found_ppid in a loop until get to ppid=1.
However, I bet, there is a single ...
- 347
1
vote
1
answer
347
views
Recall Disowned Process Mac
I'm doing some neural network training and my process needed to run for about 20 hours. Following some bad advice elsewhere I disowned my process to keep it running when I put my macbook air to sleep. ...
- 111
4
votes
1
answer
235
views
What happens when I try to use kill with a process id inferior to -1?
I’m studying for an exam and I’m not sure at all about what happens if I use kill with a pid < -1.
Am I allowed to end processes of a group in which I’m not included?
Which processes are ...
- 327
1
vote
1
answer
82
views
Why the process of sleep command is always in sleep status?
Why the process of sleep command is always in sleep status ?
Sleep status means waiting for I/O right ?
- 413
0
votes
0
answers
165
views
Why creating a process is a two-step process (fork-exec)?
I'm studying Tanenbaum's "Modern Operating Systems" book and he's explaining that:
The reason for this two-step process is to allow the child to manipulate its file descriptors after the fork but ...
- 387
5
votes
1
answer
2k
views
The OSX Process that won't die
I've got a process on OSX 10.9.5 that just won't die. I have tried
kill PID
kill -9 PID
sudo kill -9 PID
killall sshfs
killall -9 sshfs
sudo killall -9 sshfs
Activity monitor / select process / Force ...
- 245
0
votes
1
answer
51
views
Create a new process and make it use more than 10% CPU?
Really odd question I know. It's to help demonstrate my university coursework. I'm going to be killing processes that are using more than 10% of the CPU.
- 103
0
votes
1
answer
952
views
How to stop and continue the process
I used
ps -fT pid
to manage a bunch of process forked from the specified pid.
Now I want to modify some settings so I want to stop the processes whose pid is in ps -fT pid. After the modification I ...
- 501
11
votes
2
answers
21k
views
How to get list of all child process spawned by a script
Context:
Users provide me their custom scripts to run. These scripts can be of any sort like scripts to start multiple GUI programs, backend services. I have no control over how the scripts are ...
- 221
1
vote
3
answers
2k
views
Running a script where you append the errors to file and use nohup
The script works!
First I type this in my CLI: php worker.php >>/home/xxx/log 2>&1
Then, I want it to run as its own process or whatever, so I add an & at the end, like this: php ...
- 277
359
votes
11
answers
800k
views
If I know the PID number of a process, how can I get its name?
If I have the PID number for a process (on a UNIX machine), how can I find out the name of its associated process?
What do I have to do?
- 7,261
2
votes
2
answers
133
views
Monitoring a process
I'm reading documentation on supervisor, and it quotes:
It’s often difficult to get accurate up/down status on processes on
UNIX. Pidfiles often lie. Supervisord starts processes as
...
- 260
0
votes
1
answer
60
views
Create a logging program
I want to create a program that logs all the processes started by the user and confirms after they are started. I don't want to log all the syscalls and other daemon processes. I have initially ...
- 1
20
votes
4
answers
20k
views
What does kill 0 do actually?
In the man page, it says:
0 All processes in the current process group are signaled
And I tried like this:
$ man kill &
[1] 15247
$
[1]+ Stopped man kill
$ kill ...
- 313
8
votes
2
answers
43k
views
kill - no process found
when I list my processes I have:
root@adam-ThinkPad-T410:~# ps -e | grep signals
11641 pts/0 00:00:00 signals
11642 pts/0 00:00:00 signals
11643 pts/0 00:00:00 signals
but when I ...
- 181
4
votes
1
answer
451
views
Stop wget but allow convert-links
I'm running a wget command with a rather deep recursion depth. The deep recursion depth is needed to get the files I want, but I don't want to wait for the operation to complete. I see that I can ...
1
vote
2
answers
971
views
Kill a process in Unix
When I execute theps -fea | grep ssh-agent command, I get the following output:
tomcat 29057 14086 0 Jan 09 ? 0:00 ssh-agent
oracle 1964 14086 0 Nov 26 ? 0:00 ssh-...
- 119
3
votes
2
answers
5k
views
flag to 'ps' command that can filter on arguments?
I know the argument "-C" which can filter on the command.
But in my scenario I may have some processes with the same process name and different args.
How to filter on these args?
(I know I could ...
- 6,211
5
votes
1
answer
5k
views
What is session leader in `ps ax`
See the command bellow
# ps ax | grep bitlbee
2271 ? Ss 0:00 /usr/bin/bitlbee -s mysql -c /root/config.conf
3930 ? S 0:00 /usr/bin/bitlbee -s mysql -c /root/config.conf
See ...
- 878
2
votes
4
answers
591
views
Does running the 'find' command fork a new process?
When I type find in unix a shell, is a new process created (to handle the find operation) or not? And why?
user1927902
0
votes
1
answer
790
views
What is a child process?
I have an error in my error logs that I am trying to figure out but I don't know what to be looking for when it says Child Process.
I understand that its a process done by a parent, but that's an ...
Daniel Fein
2
votes
1
answer
2k
views
Why is process not being displayed by TOP
I am running a Mathematica script (this question probably doesn't fit in Mathematica.SE however) and I know that it generally takes up a lot of RAM and loads up my cores. However, althought pgrep ...
- 211
0
votes
1
answer
323
views
My sleeping process accepts TCP connections?
After sending the STOP signal to a process, it stops working as expected, but still accepts TCP connections. So is it working anyhow?
- 491
137
votes
4
answers
238k
views
What is effect of CTRL + Z on a unix\Linux application
I was curious and confused that what exactly is the behaviour of ctrl+z.
I know, If a process in running in foreground, and we press ctrl+z, it goes to background.
But what exactly happens?. Does it ...
- 1,653
0
votes
2
answers
901
views
Daemon <||> Process control differences
With respect to this excellent post:
https://stackoverflow.com/questions/958249/whats-the-difference-between-nohup-and-a-daemon
I would like to ask the following:
After launching an application ...
- 159
13
votes
5
answers
58k
views
How to find and stop a process on a Mac
How can I find the process id and stop the process that is running on port 8080 on a Mac?
On Ubuntu this works:
ps -aux
and I can find the process and run:
kill -9 pid
ps -aux didn't seem to work,...
- 1,409
3
votes
1
answer
688
views
Child processes remain after quitting screen
I'm seeing some strange screen behavior on OSX. When I quit screen, child processes are not killed.
$ screen
$ tail -f (or some long running process inside screen)
Then, I kill the current screen ...
- 31
17
votes
3
answers
38k
views
What is the main purpose of the swapper process in Unix?
What is the main purpose of the swapper process in Unix?
Swapper process has the PID 0 and I guess it is the first process that loads. Can anyone throw more light on this topic?
- 351
1
vote
1
answer
148
views
Why does Unix deliver signals this way?
In Unix, when signals are posted, and the receiving process is running more than one thread, at first a thread is chosen to carry out the signal handling routine.
I don't understand why that is ...
- 3,695
71
votes
15
answers
150k
views
ps: How can i recursively get all child process for a given pid
How can I get the entire process tree spawned by a given process displayed as a tree and only that tree i.e. no other processes?
The output could e.g. look like
4378 ? Ss 0:10 SCREEN
...
- 3,566
1
vote
1
answer
509
views
Getting the name of the previous process
I'm trying to generate notifications when certain commands finish execution. I'm trying to use xmessage or notify-send to generate this notification.
Right now, I'm trying it this way:
command; ...
- 1,607
112
votes
16
answers
114k
views
How can I trigger a notification when a job/process ends?
The place I work at has commands that take a long time to execute.
Is there a command/utility that I can use to notify me when the command execution is over? It could be a popup window or maybe a ...
- 1,607
10
votes
2
answers
8k
views
What's the Unix command-line symbol for "the PID of the last suspended process"?
In an interactive console like irb, sometimes something will go wrong and the console becomes unresponsive. One solution is to suspend the process, then kill it.
To suspend the process, I can press ...
- 27.1k
2
votes
2
answers
3k
views
How does 'strace' work?
Recently, I was using mv to move a large amount of files from my hard drive to a flash drive. I forgot to add a verbose flag so I had no idea "where" the move was at and how many transfers remained.
...
- 16.9k
0
votes
1
answer
482
views
How to identify whether a process is hanging?
In unix, if we see that some process is utilizing more cpu time, then how to identify if that process is hanging or not?
Suvitha
8
votes
2
answers
12k
views
Auto-restart process on crash [duplicate]
I have a Java server process which runs native code and the possibility of the entire process crashing due to a problem in native code is always there. Is there any mechanism offered by *nix operating ...
- 453
56
votes
8
answers
68k
views
How to run commands as in a queue
I need to do a lot of copying of various files to various folders. I can add all my copy commands to a bash script and then run that, but then I must wait until it finishes if I want to add more ...
- 40.6k
8
votes
3
answers
8k
views
How to find which Tmux session a process belongs to?
Case in point is editing a configuration file in vim and inadvertently leaving it open. Then you go about your business, switch around in different Tmux sessions, eventually edit the same file from ...
- 1,279
1
vote
3
answers
12k
views
Monitor average CPU usage and RAM usage on one process linux
Is there any way to monitor one process' CPU usage and RAM usage over time on linux? I am trying to change to a cheaper VPS and need to work out what level of CPU and RAM I need!
- 362
51
votes
4
answers
73k
views
How do you find the parent process of a zombie process?
How do you find the parent process of zombie processes?
When the child process is something where the parent is not entirely obvious...
Is there some way to list processes in tree format or ...
- 2,001
52
votes
1
answer
118k
views
In UNIX, what are the Ss, Sl, and Ssl proccess types I see with ps aux?
When doing a ps aux command, I see some process listed as Ss, Ssl and Sl.
What do these mean?
root 24653 0.0 0.0 2256 8 ? Ss Apr12 0:00 /bin/bash -c /usr/bin/python /var/...
- 741