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Linux C/C++ 呼叫外部命令，並讀取相關執行結果 GITHUB: https://github.com/jash-git/Jash_LinuxC/tree/master/Linux C呼叫外部命令_並讀取相關執行結果 https://github.com/jash-git/Jash_LinuxC/tree/master/Linux_C popen(取得PID和取得呼叫外部程式的結果) code: /* 透過 Linux C 呼叫外部命令，並讀取相關執行結果 */ #include int main(int argc, char *argv[]) { FILE *pp; char cbuffer[1280]; pp = popen("ifconfig ","r"); cbuffer[0]='\0'; while (fgets(cbuffer,sizeof(cbuffer),pp) != NULL) { printf("%s",cbuffer); cbuffer[0]='\0'; } pclose(pp); printf("\n"); return 0; } /* http://webcache.googleusercontent.com/search?q=cache:6_N6So_JZgMJ:blog.163.com/ky_147258/blog/static/14288004920118685640778/+&cd=9&hl=zh-TW&ct=clnk&lr=lang_zh-CN|lang_zh-TW linux 獲取進程ＩＤ以及popen用法等 掃描ps命令的輸出: */ /* pidof :查找運行程式的進程ID/通過進程名查看進程ID 語 法 pidof[必要參數][選擇參數][程式] 功 能 pidof 命令：可以顯示正在運行的進程ID 參數 必要參數 -s 單次選中 -c 只返回進程ID -x 同時返回腳本 選擇參數 -o 範例2： 每次只返回一個進程號 root@snail-hnlinux:~# pidof sshd -s 31327 */ #include #include #include #define PS_COMMAND "ps -ax" #define SCAN(buf) (sscanf(buf,"%d %s %s %s %s",pid,s[0],s[1],s[2],cmd) == 5) /* Returns number of pid matching process name, or -1 on error */ int lookup_pid(char *name, pid_t *pids, int n) { FILE *fp; char buf[256], cmd[200], s[3][32]; pid_t *pid; if ((fp = popen(PS_COMMAND, "r")) == NULL) return -1; pid = pids; while (n > 0 && fgets(buf, sizeof(buf), fp)) if (SCAN(buf) && strstr(cmd, name)) /* improve on this simple name check */ pid++, n--; fclose(fp); return pid - pids; } int main(int argc, char **argv) { char *process; pid_t pids[8]; int n, i; if (argc != 2) { printf("Usage: %s process_name ", argv[0]); return 1; } process = argv[1]; if ((n = lookup_pid(process, pids, 8)) == -1) { printf("Error reading pid of %s ", process); return 2; } printf("%d %s ", n, process); for (i = 0; i < n; i++) printf("%d ", pids[ i]); return 0; } #include #include #include #include #include #define READ 0 #define WRITE 1 pid_t popen2(const char *command, int *infp, int *outfp) { int p_stdin[2], p_stdout[2]; pid_t pid; if (pipe(p_stdin) != 0 || pipe(p_stdout) != 0) return -1; pid = fork(); if (pid < 0) return pid; else if (pid == 0) { close(p_stdin[WRITE]); dup2(p_stdin[READ], READ); close(p_stdout[READ]); dup2(p_stdout[WRITE], WRITE); execl("/bin/sh", "sh", "-c", command, NULL); perror("execl"); exit(1); } if (infp == NULL) close(p_stdin[WRITE]); else *infp = p_stdin[WRITE]; if (outfp == NULL) close(p_stdout[READ]); else *outfp = p_stdout[READ]; return pid; } int main(int argc, char **argv) { int infp, outfp; char buf[128]; if (popen2("sort", &infp, &outfp) <= 0) { printf("Unable to exec sort\n"); exit(1); } write(infp, "Z\n", 2); write(infp, "D\n", 2); write(infp, "A\n", 2); write(infp, "C\n", 2); close(infp); *buf = '\0'; read(outfp, buf, 128); printf("buf = '%s'\n", buf); return 0; }