create process independent of bash

I have written a program which calculates the amount of battery level available in my laptop. I have also defined a threshold value in the program. Whenever the battery level falls below threshold i would like to call another process. I have used system("./invoke.o") where invoke.o is the program that i have to run. I am running a script which runs the battery level checker prog开发者_C百科ram for every 5 seconds. Everything is working fine but when i close the bash shell the automatic invocation of invoke.o is not happening. How should i make the invoke.o to be invoked irrespective of whether bash is closed or not??. I am using UBUNTU LINUX

Try running it as: nohup ./myscript.sh, where the nohup command allows you to close the shell without terminating the process.

You could run your script as a cron job. This lets cron set up standard input and output for you, reschedule the job, and it will send you email if it fails.

The alternative is to run a script in the background with all input and output, including standard error output, redirected.

While you could make a proper daemon out of your program that kind of effort is probably not necessary.

1. man nohup
2. man upstart
3. man 2 setsid (more complex, leads to longer trail of breadcrumbs on daemon launching).