信号就是软件中断，可以向正在执行的程序(进程)发送有关异步事件发生的信息。

Signals are software interrupts that send information about an occurrence of an asynchronous event to an executing program, or process.

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除了调试core文件或程序之外，gdb还可以连接到已经运行的进程(它的程序已经过编译，并加入了调试信息)，并中断该进程。

In addition to debugging with core files or programs, GDB can attach to an already running process (who's program has debugging information compiled in) and break into it.

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更多关于应用程序部署和应用服务器重启、以避免服务中断的信息，请参阅这篇优秀的文章。

Further information on staggering application deployment and application server restarts to avoid service interruptions is available in this excellent article.

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