1．编写一个文件复制的C语言程序： 分别使用文件的系统调用read(fd, buf, nbytes), write(fd, buf, nbytes)和文件的库函数fread(buf, size, nitems, fp), fwrite(buf, size, nitems, fp)，编写一个文件的复制程序。 当上述函数中nbytes, size和nitems都取值为1时（即一次读写一个字节），比较这两种程序的执行效率。当nbytes取1024字节，size取1024字节，且nitems取1

linux进程间的通讯，利用3管道实现父进程与子进程间的双向通讯，并实现某一组函数的功能-linux inter-process communication, two-way communication using three pipelines parent process and the child process between function and to achieve a set of functions

Linux进程控制:父进程打开一个文件，然后创建两个子进程。子进程1将打开文件中的小写字母换成大写字母。子进程2将文件内容读出后打印。父进程等待两个子进程结束以后关闭文件，结束。 -Linux process control: a parent process opens a file, and then create two sub-processes. A child process will open the file in lowercase letters replaced by

QT父子进程间通讯，父进程通过writeData发送数据，子进程通过读取标准输入获取数据。-QT interval parent and child communication, the parent process to obtain data by reading standard input by writeData sending data, sub-processes.