ps -aux
pstree
int system (const char *string )
sh –c string#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
pid_t result;
printf("This is a system demo!\n\n");
/*调用 system()函数*/
result = system("ls -l");
printf("Done!\n\n");
return result;
}
#include<unistd.h>#include<sys/types.h>pid_t fork( void);
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
pid_t result;
printf("This is a fork demo!\n\n");
/*调用 fork()函数*/
result = fork();
/*通过 result 的值来判断 fork()函数的返回情况，首先进行出错处理*/
if(result == -1) {
printf("Fork error\n");
}
/*返回值为 0 代表子进程*/
else if (result == 0) {
printf("The returned value is %d, In child process!! My PID is %d\n\n", result, getpid());
}
/*返回值大于 0 代表父进程*/
else {
printf("The returned value is %d, In father process!! My PID is %d\n\n", result, getpid());
}
return result;}
int execl(const char *path, const char *arg, ...)int execlp(const char *file, const char *arg, ...)int execle(const char *path, const char *arg, ..., char *const envp[])int execv(const char *path, char *const argv[])int execvp(const char *file, char *const argv[])int execve(const char *path, char *const argv[], char *const envp[])pid_t wait(int *wstatus);
pid_t waitpid(pid_t pid, int *wstatus, int options);
#include <unistd.h>int pipe(int pipefd[2]);
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_DATA_LEN 256
#define DELAY_TIME 1
int main()
{
pid_t pid;
int pipe_fd[2]; //(1)
char buf[MAX_DATA_LEN];
const char data[] = "Pipe Test Program";
int real_read, real_write;
memset((void*)buf, 0, sizeof(buf));
/* 创建管道 */
if (pipe(pipe_fd) < 0) //(2)
{
printf("pipe create error\n");
exit(1);
}
/* 创建一子进程 */
if ((pid = fork()) == 0)
{
/* 子进程关闭写描述符，并通过使子进程暂停 3s 等待父进程已关闭相应的读描述符 */
close(pipe_fd[1]);
sleep(DELAY_TIME * 3);
/* 子进程读取管道内容 */
if ((real_read = read(pipe_fd[0], buf, MAX_DATA_LEN)) > 0)
{
printf("%d bytes read from the pipe is ‘%s‘\n", real_read, buf);
}
/* 关闭子进程读描述符 */
close(pipe_fd[0]);
exit(0);
}
else if (pid > 0)
{
/* 父进程关闭读描述符，并通过使父进程暂停 1s 等待子进程已关闭相应的写描述符 */
close(pipe_fd[0]);
sleep(DELAY_TIME);
if((real_write = write(pipe_fd[1], data, strlen(data))) != -1)
{
printf("Parent write %d bytes : ‘%s‘\n", real_write, data);
}
/*关闭父进程写描述符*/
close(pipe_fd[1]);
/*收集子进程退出信息*/
waitpid(pid, NULL, 0);
exit(0);
}
}
mkfifo
mkfifo test
#include <unistd.h>int mkfifo(const char * pathname,mode_t mode);
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#define MYFIFO "myfifo" /* 命名管道文件名*/
#define MAX_BUFFER_SIZE PIPE_BUF /* 4096 定义在于 limits.h 中*/
void fifo_read(void)
{
char buff[MAX_BUFFER_SIZE];
int fd;
int nread;
printf("***************** read fifo ************************\n");
/* 判断命名管道是否已存在，若尚未创建，则以相应的权限创建*/
if (access(MYFIFO, F_OK) == -1)
{
if ((mkfifo(MYFIFO, 0666) < 0) && (errno != EEXIST))
{
printf("Cannot create fifo file\n");
exit(1);
}
}
/* 以只读阻塞方式打开命名管道 */
fd = open(MYFIFO, O_RDONLY);
if (fd == -1)
{
printf("Open fifo file error\n");
exit(1);
}
memset(buff, 0, sizeof(buff));
if ((nread = read(fd, buff, MAX_BUFFER_SIZE)) > 0)
{
printf("Read ‘%s‘ from FIFO\n", buff);
}
printf("***************** close fifo ************************\n");
close(fd);
exit(0);
}
void fifo_write(void)
{
int fd;
char buff[] = "this is a fifo test demo";
int nwrite;
sleep(2); //等待子进程先运行
/* 以只写阻塞方式打开 FIFO 管道 */
fd = open(MYFIFO, O_WRONLY | O_CREAT, 0644);
if (fd == -1)
{
printf("Open fifo file error\n");
exit(1);
}
printf("Write ‘%s‘ to FIFO\n", buff);
/*向管道中写入字符串*/
nwrite = write(fd, buff, MAX_BUFFER_SIZE);
if(wait(NULL)) //等待子进程退出
{
close(fd);
exit(0);
}
}
int main()
{
pid_t result;
/*调用 fork()函数*/
result = fork();
/*通过 result 的值来判断 fork() 函数的返回情况，首先进行出错处理*/
if(result == -1)
{
printf("Fork error\n");
}
else if (result == 0) /*返回值为 0 代表子进程*/
{
fifo_read();
}
else /*返回值大于 0 代表父进程*/
{
fifo_write();
}
return result;
}
kill -lkill [信号或选项] PID(s)#include <sys/types.h>
#include <signal.h>
int kill(pid_t pid, int sig);
#include <signal.h>
int raise(int sig);
#include <unistd.h>
unsigned int alarm(unsigned int seconds);#include <signal.h>
typedef void (*sighandler_t)(int);
sighandler_t signal(int signum, sighandler_t handler);
void(*sighandler_t)(int) 类型sigaction();#include <signal.h>
int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact);
signum：指定捕获的信号值
act：是一个结构体
struct sigaction {
void (*sa_handler)(int);
void (*sa_sigaction)(int, siginfo_t *, void *);
sigset_t sa_mask;
int sa_flags;
void (*sa_restorer)(void);
};
siginfo_t {
int si_signo; /* 信号数值 */
int si_errno; /* 错误值 */
int si_code; /* 信号代码 */
int si_trapno; /*导致硬件生成信号的陷阱号，在大多数体系结构中未使用*/
pid_t si_pid; /* 发送信号的进程ID */
uid_t si_uid; /*发送信号的真实用户ID */
int si_status; /* 退出值或信号状态*/
clock_t si_utime; /*消耗的用户时间*/
clock_t si_stime; /*消耗的系统时间*/
sigval_t si_value; /*信号值*/
int si_int; /* POSIX.1b 信号*/
void *si_ptr;
int si_overrun; /*计时器溢出计数*/
int si_timerid; /* 计时器ID */
void *si_addr; /*导致故障的内存位置 */
long si_band;
int si_fd; /* 文件描述符*/
short si_addr_lsb; /*地址的最低有效位 (从Linux 2.6.32开始存在) */
void *si_lower; /*地址冲突时的下限*/
void *si_upper; /*地址冲突时的上限 (从Linux 3.19开始存在) */
int si_pkey; /*导致的PTE上的保护密钥*/
void *si_call_addr; /*系统调用指令的地址*/
int si_syscall; /*尝试的系统调用次数*/
unsigned int si_arch; /* 尝试的系统调用的体系结构*/
}
#include <signal.h>int sigemptyset(sigset_t *set);
int sigfillset(sigset_t *set);
int sigaddset(sigset_t *set, int signum);
int sigdelset(sigset_t *set, int signum);
int sigismember(const sigset_t *set, int signum);
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
/** 信号处理函数 **/void signal_handler(int sig) //(1){
printf("\nthis signal numble is %d \n",sig);
if (sig == SIGINT) {
printf("I have get SIGINT!\n\n");
printf("The signal is automatically restored to the default handler!\n\n");
/** 信号自动恢复为默认处理函数 **/
}
}
int main(void){
struct sigaction act;
printf("this is sigaction function test demo!\n\n");
/** 设置信号处理的回调函数 */
act.sa_handler = signal_handler;
/* 清空屏蔽信号集 */
sigemptyset(&act.sa_mask);
/** 在处理完信号后恢复默认信号处理 */
act.sa_flags = SA_RESETHAND;
sigaction(SIGINT, &act, NULL);
while (1)
{
printf("waiting for the SIGINT signal , please enter \"ctrl + c\"...\n\n");
sleep(1);
}
exit(0);
}
* 野火原文：https://www.cnblogs.com/lizhuming/p/14203037.html