Questions tagged [sighup]

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When does a hup signal affect the parent process? [duplicate]

If I run ./script.sh &, where script is the following: #!/bin/bash echo "hello" sleep 30 echo "hello again" sleep 30 touch /root/foo.txt Then I use ps au, to identify the &...
Thomas Stokes's user avatar
3 votes
1 answer
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Surprise: Interactive Bash runs commands in a separate Process Group

I am surprised that at least from Bash 4.4.19, Interactive Bash runs commands in a separate session, see following process list after I run sleep 8888: PGID PID PPID 3150071 3150071 252603 ...
osexp2000's user avatar
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xargs nano leads to Received SIGHUP or SIGTERM while xargs less is OK

Scenario: $ cat t0.txt t1.txt $ cat t1.txt xxx $ sed -n 1p t0.txt | xargs less # OK $ sed -n 1p t0.txt | xargs nano Received SIGHUP or SIGTERM dvl-linux64 $ nano --version GNU nano, version 2.5.3 ...
pmor's user avatar
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1 vote
0 answers
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Can't create new file with nano, Received SIGHUP or SIGTERM

I found only this question of this subject: Received SIGHUP or SIGTERM: nano cannot edit empty file I'm configuring my web server. There wasn't any problems earlier and I would like to know exactly ...
MiQuela's user avatar
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2 votes
1 answer
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Why does huponexit not work in the following?

Bash manual says If the huponexit shell option has been set with shopt (see Section 4.3.2 [The Shopt Builtin], page 62), Bash sends a SIGHUP to all jobs when an interactive login shell exits. ...
Tim's user avatar
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3 answers
1k views

Why does closing terminal emulator window terminate a bash process with SIGHUP trap changed not to terminate?

In a bash shell in a terminal emulator window of lxterminal, I run $ trap "echo hello" SIGHUP $ kill -s HUP $$ hello $ and then I close the terminal emulator window. Does closing the terminal ...
Tim's user avatar
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-2 votes
1 answer
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Why doesn't the Linux kernel send SIGCONT first and then SIGHUP to a newly orphaned process group containing a stopped process?

APUE says Since the process group is orphaned when the parent terminates, and the process group contains a stopped process, POSIX.1 requires that every process in the newly ...
Tim's user avatar
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6 votes
1 answer
1k views

Why do we need to send SIGHUP to a newly orphaned process group containing a stopped process?

The Advanced Programming in the UNIX Environment book ("APUE") says Consider a process that forks a child and then terminates. Although this is nothing abnormal (it happens all the time), ...
Tim's user avatar
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1 vote
1 answer
608 views

How can I stop a child process of a subshell (as per SIGSTOP) before the subshell exits?

In bash, when running ( sleep 123 &), the sleep 123 process will continue running, when the subshell exits. How can I stop the sleep 123 process before its parent subshell exits? I'm trying to ...
Tim's user avatar
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2 votes
1 answer
658 views

Does kernel sending SIGHUP to a process group that becomes orphaned and contains a stopped process terminate all the processes by default?

In The Linux Programming Interface To see why orphaned process groups are important, we need to view things from the perspective of shell job control. Consider the following scenario based on ...
Tim's user avatar
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3 votes
1 answer
843 views

Is SIGHUP sent to this orphaned process, and why doesn't it terminate?

In The Linux Programming Interface: SIGHUP is generated when a process group becomes orphaned. In an interactive bash process, $ ( sleep 123 &) will first forks a subshell, and the ...
Tim's user avatar
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2 votes
1 answer
1k views

Does nohup apply only to a child process of a shell process, but not to a child process of a non-shell process?

nohup is an external program. How can it change the action of SIGHUP by a child process of a shell process to be "ignore"? (in terms of some arguments when the child process invokes fork() and/or ...
Tim's user avatar
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1 vote
1 answer
525 views

Who sends SIGHUP to the controlling process of the pseudoterminal when the terminal emulator terminates?

When a terminal is disconnected, the OS kernel sends SIGHUP to the controlling process of the terminal. When a terminal emulator terminates, who sends SIGHUP to the controlling process of the ...
Tim's user avatar
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8 votes
2 answers
17k views

Why is kill -HUP used in logrotate in RHEL? Is it necessary in all cases?

I see for syslog logging, kill -HUP is used. /var/log/cron /var/log/maillog /var/log/messages /var/log/secure /var/log/spooler { sharedscripts postrotate /bin/kill -HUP `cat /var/run/...
GP92's user avatar
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trapping HUP/SIGHUP is not working in bash script

I have this bash script: https://gist.github.com/ORESoftware/06dbb26a48d2ddf48a5a2166834e0836 when I call ql_acquire_lock in a shell, if I can call mkdir on a directory, then I acquire that lock. ...
Alexander Mills's user avatar