Saturday, May 29, 2010

Signals from the Command Lines

Read an interesting article from LINUX format May 2010 on "Sending the right signal". Learned quite a bit from this article on signals.

Name: SIGHUP 
No: 1
Description. Tells a daemon that its configuration file has changed and named to be re-read
Default action: Terminate

Name: SIGINT
No: 2
Description: SIGINT is sent to the foreground process when you type Ctrl + C. It terminate the process
Default action: Terminate

Name: SIGQUIT
No: 3
Description: SIGQUIT is sent to the foreground process and you type Ctrl + \. It terminate the process with a core dump
Default action: Terminate with core dump.
Note: For Fedora, the core file are suppressed. You can check with the command umlimit -a

Name: SIGKILL
No: 9
Description: Extreme signal that can't be caught or ignored.
Default action: Terminate

Name: SIGSEGV
No: 11
Description: It is sent from within the the program when it tried to access a memory that is not in it allocated range. The memory management hardwre notice the attempt and inform the kernel which send a SIGSEGV to terminate the program

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