#include <stdlib.h> #include <string.h> #include <stdio.h> #include <fcntl.h> #include <unistd.h> static int getResultFromSystemCall(const char* pCmd, char* pResult, int size) { int fd[2]; if(pipe(fd)) { printf("pipe error!\n"); return -1; } //hide stdout int bak_fd = dup(STDOUT_FILENO); int new_fd = dup2(fd[1], STDOUT_FILENO); //the output of `pCmd` is write into fd[1] system(pCmd); read(fd[0], pResult, size-1); pResult[strlen(pResult)-1] = 0; //resume stdout dup2(bak_fd, new_fd); return 0; } int main(void) { char* filePath = "./test.conf"; char* key = "aaa"; char res[100] = {0}; char cmd[100] = {0}; sprintf(cmd, "cat %s | grep -m 1 -E \"^%s\" | cut -d= -f2 | sed 's/[[:space:]]*//g'", filePath, key); getResultFromSystemCall(cmd, res, sizeof(res)/sizeof(res[0])); //getResultFromSystemCall("export aaa=1234 && echo ${aaa#=}", res, sizeof(res)/sizeof(res[0])); printf("result is [%s]\n", res); return 0; }