Questions tagged [signals]
The signals tag has no usage guidance.
34
questions
25
votes
4
answers
18k
views
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 ...
- 71.3k
23
votes
2
answers
10k
views
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). ...
- 425
17
votes
4
answers
16k
views
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?
- 629
14
votes
4
answers
13k
views
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.
- 1,171
13
votes
2
answers
7k
views
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 ...
- 1,684
9
votes
2
answers
20k
views
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 ...
- 91
8
votes
2
answers
5k
views
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 ...
- 355
6
votes
1
answer
425
views
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 ...
- 163
5
votes
3
answers
13k
views
Letting systemd service to stop later without blocking on `systemctl stop`
I have bunch of services responsible for running action consumed from the queue.
I want to be able to restart services gently (without interrupting action which're already running)
It can be solved ...
- 211
4
votes
1
answer
2k
views
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 ...
4
votes
1
answer
7k
views
whats the difference between sigkill and sigabrt? [closed]
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 ...
- 153
4
votes
3
answers
4k
views
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. ...
- 1,545
3
votes
2
answers
3k
views
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 ...
- 677
3
votes
7
answers
675
views
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 ...
- 502
3
votes
1
answer
231
views
How to find which process sent a HUP signal to my node.js process?
Every Monday at 9AM UTC something sends a HUP signal to my node.js process (and I think HUP is being sent to all processes, not just mine). How do I find which process sent the HUP signal to my ...
user3903
3
votes
1
answer
824
views
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 ...
- 31
2
votes
2
answers
2k
views
kill -HUP is not working with celery daemon
So I have a shell script that daemonizes celery, and creates a bunch of workers running as a daemon. I would like to have a way to restart the celery task when the underlying source gets changed since ...
- 145
2
votes
1
answer
602
views
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 ...
- 131
1
vote
2
answers
4k
views
Logging Linux processes which exit because of a signal?
While running FreeBSD a long time ago, there was a default feature which logged when a process received one of the fatal signals, like SIGSEGV, SIGBUS, SIGKILL, etc. and was terminated because of that....
- 186
1
vote
2
answers
2k
views
Apache Kafka 0.8.1.1 clean shutdown not working
I have a:
single instance of Apache Kafka (2.9.2-0.8.1.1) installed from the source, using the default configuration (server.properties etc.),
Zookeeper (3.4.5+dfsg-2) stand-alone, installed from the ...
- 1,341
1
vote
0
answers
69
views
Server keep restarting after reaching 'starting web server'
Recently one of our server failed and wont start services. I looked over the /var/log/messages and found this:
Dec 27 00:53:48 localhost apcupsd[3413]: apcupsd FATAL ERROR in linux-usb.c at line 609 ...
- 111
1
vote
0
answers
1k
views
How to write a bash script that traps SIGTERM and kills the process and all sub-processes immediately
I have this script:
#!/bin/bash
set -e
#WHAT SHOULD I WRITE HERE?
sleep 60 # this is for testing
#java ... | logger # this is what will be in the real script
I want to be able to kill myscript and ...
- 229
1
vote
0
answers
504
views
Linux: Process ignores signals
Processes running in Linux ignores signals (INT,QUIT,TERM) except KILL. Programs such as top, tail -f, sleep and etc, do not respond when pressing Ctrl+C and thus have to stop them from another ...
- 243
1
vote
0
answers
362
views
Unexpected jBoss crash and auditing signals
We're experiencing unexpected JBoss crashes on a semi-regular basis. JBoss 5 is running on RHEL6 in this case.
I believe this is related to a sigusr1 sent to the JBoss process. The JBoss server logs ...
- 1,749
0
votes
2
answers
251
views
How can I use symbolic signals in an at job?
In this answer on SO, I gave an example that should have used a -SIGCONT signal in a job submitted to at. However, I found that the process that I had stopped with -SIGSTOP did not continue. When I ...
0
votes
2
answers
1k
views
Unicorn retains same PID when receives USR2?
So, I've been playing with a unicorn deployment on my personal server. There are a variety of reasons behind this - one of them being that I didn't particularly want to have to compile my own version ...
- 141
0
votes
2
answers
2k
views
PostgreSQL processes and the signals to which they respond
For PostgreSQL 8.3 and later, what are the processes that make up the server and that respond to a query?
What signals do the various processes respond to and what effect do the signals have?
What ...
- 1,004
0
votes
1
answer
4k
views
ssh remote command: Killed by signal 15
script:
#!/usr/bin/env bash
set -e
set -u
set -x
set -o pipefail
hosts=(
host1
host2
)
for host in ${hosts[@]}
do
ssh $host 'pids=$(ps -aux|pgrep -f "/usr/bin/nmon"); kill $pids; wait $...
- 109
0
votes
1
answer
236
views
ubuntu upstart never killing my process
I have a simple bash script:
echo "Starting"
function sigint {
echo "sigint"
}
function sigterm {
echo "sigterm"
}
trap sigterm SIGTERM
trap sigint SIGINT
while true
do
sleep 2
echo "-"
...
- 231
0
votes
1
answer
262
views
Logging violations of rules in limits.conf
I am trying to log the details of the programs that where failed due to the limit cap defined in the limits.conf. My initial plan was to do it using the audit system. The idea was to track the system ...
- 149
0
votes
2
answers
4k
views
Process that sent SIGKILL
I have a series of scripts that are being killed ($? says exit code is 137, which implies a kill -9 scenario). I need to know what process killed them. Is there a way to find out this information?
- 1,556
0
votes
0
answers
105
views
Ctrl-C is ignored by pppd when put in a shell script
I'm trying to connect to GPRS network through a serial port connected GSM modem.
When I call /usr/sbin/pppd call <peer_name> from the command line, It correctly receives and handles Ctrl+C from ...
- 161
-1
votes
1
answer
108
views
Wifi Signal Strengths [closed]
I hope that I have asked this question in the right topic.
Basically I use BT (In the U.K.) and I have problems with my router receiving a weak signal in certain rooms of the house, which, therefore ...
- 101
-2
votes
1
answer
1k
views
How to mask out wireless by blocking a neighboring WiFi Access Point [closed]
I surely hope this question is not a duplicate of another; I had difficulty finding a cut and dry solution for this on my own, so I thought I might have some luck sharing it with the Hive Mind of ...
- 109