Unix: Dealing with signals
On Unix systems, there are several ways to send signals to processes—with a kill command, with a keyboard sequence (like control-C), or through your own program (e.g., using a kill command in C). Signals are also generated by hardware exceptions such as segmentation faults and illegal instructions, timers and child process termination.
But how do you know what signals a process will react to? After all, what a process is programmed to do and able to ignore is another issue.
Fortunately, the /proc file system makes information about how processes handle signals (and which they block or ignore) accessible with commands like the one shown below. In this command, we’re looking at information related to the login shell for the current user, the "$$" representing the current process.
To read this article in full or to leave a comment, please click here