I'm running into a weird behavior for a certain app I'm using. If I start the command in the background in bash, I can kill it using
$ command &
$ kill -n 2 [PID of command]
killing command gracefully
However, when I throw this into a script:
command &
ID=$!
kill -n 2 $ID
it doesn't do anything at all. Is there some subtly I'm missing?
Edit: Another clue is that once the script stops running, I can't kill the command using kill -n 2.
man 7 signal You are sending a signal 2, INT, to your process, that is Interrupt from keyboard, why ? People are saying to send a signal 1, why ?
The standard gracefully way to kill a process is signal 15, Termination sigal, that is the default used by kill.
So just use kill "$PID"
Then, in case your process run subprocess, you don't just want to kill the father, but you want to kill them all, so use "-$PID" instead of "$PID" to kill the whole process group, but as kill will think that's -"$PID" is a signal number, it will complain, so you'll have to be more precise, as :
kill -15 -"$PID"
If the program don't want to die, use kill -9 -"$PID"
man 7 signal
man kill
Your $ID matches a command string, while what you need is a PID. Maybe try this:
ID=`pidof -s command`
kill -9 $ID
If you command outputs to the terminal, bash will stop it with SIGSTOP, which will make it ignore SIGINT you are sending.
This probably isn't your problem, but the -n is an option for bash's built-in kill command. I would suggest using -NAME instead so that it works for the actual command too.
Add a wait command right after your kill.
It seems that in case the command is run from a script, it will handle/ignore some signals. Nevertheless, you can still kill the process with SIGKILL (1) like this:
kill -n 1 $ID
ID=command&doesn't do what you think.