Linux 生成 core dump的方法及设置

core dump 定义
A core dump is the recorded state of the working memory of a computer program at a specific time, generally when the 
program has terminated abnormally (crashed). In practice, other key pieces of program state are usually dumped at 
the same time, including the processor registers, which may include the program counter and stack pointer, memory 
management information, and other processor and operating system flags and information. The name comes from the 
once-standard memory technology core memory. Core dumps are often used to diagnose or debug errors in computer programs.

On many operating systems, a fatal error in a program automatically triggers a core dump, and by extension the phrase 
"to dump core" has come to mean, in many cases, any fatal error, regardless of whether a record of the program memory 
is created.