typicalzoe的专栏

1）execvp execvp（执行文件） 相关函数 fork，execl，execle，execlp

1. Sigactionint sigaction(int signum, const struct sigaction *act, struct sigaction *oldact);int sigprocmask(int how, const sigset_t *set, sigset_t *oldset);int sigpending(sigset_t *set);int sigsu