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218
votes
9answers
97k views

When should I not kill -9 a process?

I am always very hesitant to run kill -9, but I see other admins do it almost routinely. I figure there is probably a sensible middle ground, so: When and why should kill -9 be used? When and why ...
11
votes
9answers
4k views

Ensure a process is always running

I started hosting sites a while back using Cherokee. For external sources (FastCGI, etc) it has an option to launch the process if it can't find one running on the designated socket or port. This is ...
11
votes
6answers
8k views

How to make a process invisible to other users?

How could you launch a process and make it invisible to the top command? The process is started by a normal user (not root), and should not be visible to other normal users.
12
votes
2answers
4k views

Per process firewall?

I've been reading around but can't seem to find a way to create per-process firewall rules. I know about iptables --uid-owner but that only works for outgoing traffic. I've considered scripting ...
13
votes
2answers
18k views

How can I kill a <defunct> process whose parent is init?

Transmission is intermittently hanging on my NAS. If I send SIGTERM, it doesn't disappear from the process list and a <defunct> label appears next to it. If I send a SIGKILL, it still doesn't ...
16
votes
4answers
2k views

What happens if you edit a script during execution?

I have a general question, which might be a result of misunderstanding of how processes are handled in Linux. For my purposes I am going to define a 'script' as a snippet of bash code saved to a text ...
6
votes
1answer
10k views

What does this process STAT indicates?

If you check the STAT column in above image you will see Ss S S< SN and R+ What does this indicates ? Process states. If yes,Then what is the significance of 'Ss S< SN and R+'?
29
votes
2answers
2k views

Why is the default process creation mechanism fork?

The UNIX system call for process creation, fork(), creates a child process by copying the parent process. My understanding is that this is almost always followed by a call to exec() to replace the ...
13
votes
2answers
2k views

Getting a window's PID by clicking on it

Is there any package which shows PID of a window by clicking on it?
25
votes
4answers
2k views

python vs bc in evaluating 6^6^6

I am evaluating the expression 6^6^6 using python and bc separately. The content of the python file is print 6**6**6. When I execute time python test.py, I get the output as real 0m0.067s ...
5
votes
3answers
30k views

How can I see what processes are running?

I use Ubuntu Server 10.10 and I would like to see what processes are running. I know that PostgreSQL is running on my machine but I can not see it with the top or ps commands, so I assume that they ...
15
votes
1answer
5k views

What is the maximum value of the PID of a process?

What is the maximum value of the PID of a process? Also, is it possible to change the PID of a running process?
6
votes
4answers
6k views

'kill java' doesn't kill java

I am running debian right now and sometimes I need to kill java manually from the terminal, but when I try kill #pid# or pkill java nothing happens. No console output (ok, that's normal) and java is ...
7
votes
1answer
146 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 ...
3
votes
2answers
215 views

Running a daemon as a non-privileged user

I am trying to set up a Thin Ruby application server on my Ubuntu VPS. I have created a specific account, installed rbenv under it along with all gems. I am looking for a convenient way to obtain the ...
1
vote
3answers
121 views

How do I start a server via ssh and have it run after I log out?

I ssh into a virtual server and start up a web server. Everything runs as expected. But when I close my terminal on my laptop, the process dies on the virtual server. How do I fix this?
1
vote
2answers
120 views

Terminal command (called not from SU) that would restrict process from writting to all directories but one?

We have an app testApp. We have a folder called notRestricted in the directory where we run app from. We want to limit access of the app to file system so that app could write only to that folder (we ...
0
votes
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 ?