如何优雅的杀死linux进程?
1.通过PID进程号杀死进程
kill -9 pid （强制杀死进程）
kill -15 pid （正常结束进程）
2.通过进程名杀死进程（精确 交互 正则）
安装：yum install psmisc -y
killall 进程名 （杀死所有有关于进程名的进程，包括父进程与子进程）
killall -e (对进程名称进行精确匹配)
killall -i (交互杀死进程)
killall -r (正则匹配要杀死的进程名称)
ps -ef |grep "进程名"| grep -v grep|awk '{print $2}'|xargs kill -9 （对进程通过grep匹配后杀死，也可以用zgrep做正则匹配）
3.进程组是什么；如何杀死进程组的所有进程；只杀进程组部分的进程，进程组是否会消失
[root@WIN-2IOOCRIFKT6 tools]#ps -ejH|head -n 1 PID PGID SID TTY TIME CMD
PGID：进程组ID
SID:会话组ID
linux之进程的基本概念(进程，进程组，会话关系）_草上爬的博客-CSDN博客_进程组
执行： killall -g
4.杀死某用户的所有进程（尝试一下root）
killall -u 用户名
5.编译自己的kill程序
原理：向Linux系统的内核发送一个系统操作信号和某个程序的进程标识号，然后系统内核就可以对进程标识号指定的进程进行操作
#include #include #include #include #include #include const char *signm[] = { 0,"HUP", "INT", "QUIT", "ILL", "TRAP", "IOT", "EMT", "FPE",/* 1-8 */"KILL", "BUS", "SEGV", "SYS", "PIPE", "ALRM", "TERM", 0,/* 9-16 */"STOP", "TSTP", "CONT", "CHLD", "TTIN", "TTOU", "TINT", "XCPU",/* 17-24 */"XFSZ", 0, 0, 0, 0, 0, 0, 0,/* 25-31 */};static void usage(void){(void)fprintf(stderr, "%s\n%s\n%s\n%s\n","usage: kill [-s signal_name] pid ...","kill -l [exit_status]","kill -signal_name pid ...","kill -signal_number pid ...");#ifdef SHELLerror(NULL);#elseexit(2);#endif}static void printsignals(FILE *fp){int n;for (n = 1; n < NSIG; n++) {(void)fprintf(fp, "%s", signm[n]);if (n == (NSIG / 2) || n == (NSIG - 1))(void)fprintf(fp, "\n");else(void)fprintf(fp, " ");}}static void nosig(const char *name){warnx("unknown signal %s; valid signals:", name);printsignals(stderr);#ifdef SHELLerror(NULL);#elseexit(2);#endif}static int signame_to_signum(const char *sig){int n;if (strncasecmp(sig, "SIG", 3) == 0)sig += 3;for (n = 1; n < NSIG; n++) {if (!strcasecmp(signm[n], sig))return n;}return -1;}int main(int argc, char *argv[]){long pidl;pid_t pid;int errors, numsig, ret;char *ep;if (argc 1)usage();if (argc == 1) {if (!isdigit(**argv))usage();numsig = strtol(*argv, &ep, 10);if (!**argv || *ep)errx(2, "illegal signal number: %s", *argv);if (numsig >= 128)numsig -= 128;if (numsig = NSIG)nosig(*argv);printf("%s\n", signm[numsig]);return (0);}printsignals(stdout);return (0);}if (!strcmp(*argv, "-s")) {argc--, argv++;if (argc < 1) {warnx("option requires an argument -- s");usage();}if (strcmp(*argv, "0")) {if ((numsig = signame_to_signum(*argv)) < 0)nosig(*argv);} elsenumsig = 0;argc--, argv++;} else if (**argv == '-' && *(*argv + 1) != '-') {++*argv;if (isalpha(**argv)) {if ((numsig = signame_to_signum(*argv)) < 0)nosig(*argv);} else if (isdigit(**argv)) {numsig = strtol(*argv, &ep, 10);if (!**argv || *ep)errx(2, "illegal signal number: %s", *argv);if (numsig 0 && strncmp(*argv, "--", 2) == 0)argc--, argv++;if (argc == 0)usage();for (errors = 0; argc; argc--, argv++) {#ifdef SHELLif (**argv == '%')ret = killjob(*argv, numsig);else#endif{pidl = strtol(*argv, &ep, 10);/* 检查pid_t 是否溢出 */pid = (pid_t)pidl;if (!**argv || *ep || pid != pidl)errx(2, "illegal process id: %s", *argv);ret = kill(pid, numsig);}if (ret == -1) {warn("%s", *argv);errors = 1;}}return errors;}执行步骤：
1. g++ kill.cpp -o killguoan
2../killguoan -9 pid
6. killall5 它向所有进程发送一个信号，除了内核线程和它自己会话中的进程
killall5 （关闭除内核和当前shell中的所有进程）
killall5 -o pid （关闭除pid外的所有进程）