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Questions tagged [signals]

34 questions
22
votes
2 answers

Configure buggy systemd service to terminate via SIGKILL

Background I've been asked to create a systemd script for a new service, foo_daemon, that sometimes gets into a "bad state", and won't die via SIGTERM (likely due to custom signal handler). This is problematic for developers, as they are instructed…
Cloud
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4 answers

Do background processes get a SIGHUP when logging off?

This is a followup to this question. I've run some more tests; looks like it really doesn't matter if this is done at the physical console or via SSH, neither does this happen only with SCP; I also tested it with cat /dev/zero > /dev/null. The…
Massimo
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17
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4 answers

I get Killed by signal 15. when I'm using svn

I'm using svn+ssh and I see a number of: Killed by signal 15. during a svn up. Any ideas way?
Noah Campbell
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13
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4 answers

How to find out the source of a POSIX signal

Is there a way to find out the origin of a signal sent in Red Hat Enterprise Linux 5 (SIGTERM etc.)? I'm regularly trapping a TERM in an application and I have no idea where it is coming from.
user27451
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13
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2 answers

Wireless link frequency choice (900Mhz vs 5.8Ghz) for 2-3km distance

I have recently been contracted by a client of mine to facilitate the wireless communication of his "home" offices and a secondary site. The primary site is the top two floors of a 5-story office building (15m height more or less) an the secondary…
dlyk1988
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9
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2 answers

Industry standard for minimum Wifi signal strength?

Is there an industry standard for how strong a Wifi signal needs to be in order to have a reliable connection? For example, maybe Wifi endpoints are designed to the specification that they connect reliably to a -70db signal. We're designing a Wifi…
user163521
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6
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1 answer

Is it generally safe to use SIGCONT on processes?

I have a many daemon processes that sometimes get hung up during a db transaction, thus blocking other queries ( and causing general havoc ) In order to debug, I've added some code in the daemon process to dump a stacktrace when a SIGCONT signal is…
deadkarma
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4
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1 answer

Ctrl+C no longer working to get a new blank line in bash

I have been using Ctrl+C on most terminals to easily cancel the line I was writing and open the way for a new line. (I'm not talking about killing a running bash script, but just opening a new blank line) For no reason I can think of, this…
Cyril Duchon-Doris
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4
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3 answers

What does the Ubiquiti Bullet do?

I was briefly shown the networking setup for a rural hospital campus. Some of the things I was told or shown are: There is an 802.11b signal, broadcast over an omnidirectional antenna on a tower. This network is password-protected. 802.11b was…
Nathan Long
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3
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1 answer

whats the difference between sigkill and sigabrt?

The other day I experienced a halt in my python application with sigabrt, but I knew that the init should send a sigkill signal. I'm curious what's the difference between them, if any? Can someone give me some resources to read more about this?
Rohola Zandie
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3
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7 answers

Wireless network signal strength troubleshooting... where to start?

Here is the information displayed by the wireless router (see end of post). The problem is that my netbook does not get any signals from the router if moved more than 3 feet (yup, three feet) away from the router. Please outline steps that I should…
Salman A
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3
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2 answers

Modifiying parameters in postgresql.conf and SIGHUP

I modified the parameter maintenance_work_mem in postgresql.conf in my production environment. I'd like to know if I send a SIGHUP to the postgres process it will reload that variable, and if it's safe for such environment.
xain
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1 answer

transparent signals over ssh

By transparently I mean forwarding of: stdin, stdout and stderr standard signals (SIGHUP or SIGINT would be great for a start) As an example, consider these invocations of a (pointless) local and remote command: $ `cat - > /dev/null; sleep 10` <…
jnsg
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2 answers

How to send a signal to a Docker container without affecting restart policy?

TIL that docker kill means kill in the sense of "make it dead", as opposed to the POSIX sense of "send a signal". We have several containers that we need to send a SIGHUP to in order to reload configuration, but this causes them to ignore their…
leedm777
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1 answer

Process inside docker container not receiving signals?

I have a process in a docker container that is supposed to log a thread dump (on stdout) when shut down. However when docker stop is called on it, no output happens. It seems that either the process doesn't receive the TERM signal or the output is…
Svante
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