CODEWITHSUNDEEP
linuxsignalskill
Hao Shen
Hao Shen

Reputation: 2735

Is it possible to use "kill" to send a signal to a process without forcing the process to exit?

I have a shell script in which I can use "trap" command to capture the signals sent.

It will execute some function when specific signals are received.

I use the "kill" command to send the signal.

I just want to trigger the function in the script while not really kill the script.

Originally I thought the SIGUSR1 and SIGUSR2 should work, but I am wrong, the script just exited.

So is there a way to just use kill to send a signal to trigger some functions without really killing the process?

Upvotes: 1

Views: 1367

Answers (2)

RoundSparrow hilltx
RoundSparrow hilltx

Reputation: 799

I believe it's rarely used, but I know of one common case you can reference.

dd

you can send a USR1 signal to dd while running and it will output progress. Entirely userland and works great, fully portable code too. Reference: http://en.wikipedia.org/wiki/Dd_(Unix)

Upvotes: 3

Drgnkght
Drgnkght

Reputation: 121

According to the man pages for kill and signal(7), the best you could hope for would be to stop and then maybe continue. But I don't think that will do what you want. I also question the desire to use "kill", a command whose name makes its intended purpose very clear, to do this. Almost every signal you can send with kill is intended to terminate a process or cause it to dump core. I'm not an expert but I think you are trying to use the wrong tool here.

Upvotes: 1

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