System initialization files.

0、1和2分别表示标准输入、标准输出和标准错误信息输出

 

0: 标准输入

1: 标准输出

2: 标准错误

 

>: Redirect standard output

1>: The same as last one, redirect standard output

2>: Redirect standard error

&>: Redirect both standard error and standard output

 

 

>, overwrite

>>, append

< input