本实验父进程从控制台读数据，并向管道中写字符串。子进程将父进程经由管道传输过来的字符进行大小写互转，然后将装换后的字符送回父进程。-In this study, the parent process read data from the console, write to the pipe string. The child process the parent process through the tunnel over the character case conversion, and then loaded back for the character after the parent process.