ftp服务器设计成为一个守护进程，程序接受三个参数start,stop,restart。程序捕获SIGHUP、SIGQUIT、SIGCHLD、SIGPIPE信号并做相应处理，实现FTP所以命令列表。-ftp server designed as a daemon, the program to accept three arguments start, stop, restart. Program to capture SIGHUP, SIGQUIT, SIGCHLD, SIGPIPE sign

GPS信号的捕获跟踪，适合GPS信号。有需要的同学可以下来学习一下。-The capture of the GPS signal tracking, suitable for GPS signals. Needy students down to learn.

北邮计算机网络的大作业，模拟网络传输过程，捕获信号-Great job BUPT computer network, the analog network transmission process, capture signal