制作Linux shell时流重定向和管道

execute()的作用是遍历数组.如果遇到<,>或|它应该采取适当的行动.我试图正常工作的第一件事是管道.不过,我肯定做错了,因为即使是一个烟斗也无法让它工作.例如,一个示例输入/输出：

/home/ad/Documents> ls -l | grep sh
|: sh: No such file or directory
|

我的想法是让每个方向和管道仅适用于一个案例,然后通过使函数递归,我希望在同一命令行中使用多个重定向/管道.例如,我可以做program1< input1.txt> output1.txt或ls -l | grep sh> output2.txt.

我希望有人可以在尝试管道时指出我的错误,并且可能提供一些关于如何处理用户输入多个重定向/管道的情况的指示.

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <String.h>
#include <stdlib.h>

int MAX_PATH_LENGTH = 1024; //Maximum path length to display.
int BUF_LENGTH = 1024; // Length of buffer to store user input
char * delims = " \n"; // Delimiters for tokenizing user input.
const int PIPE_READ = 0;
const int PIPE_WRITE = 1;

void execute(char **argArray){

  char **pA = argArray;
  int i = 0;
  while(*pA != NULL) {
    if(strcmp(argArraY[i],"<") == 0) { 
        printf("<\n"); 
    }
    else if(strcmp(argArraY[i],">") == 0) { 
        printf(">\n"); 
    }
    else if(strcmp(argArraY[i],"|") == 0) {
        int fds[2];
        pipe(fds);
        pid_t pid;
        if((pid = @L_607_18@) == 0) {
            dup2(fds[PIPE_WRITE],1);
            close(fds[PIPE_READ]);
            close(fds[PIPE_WRITE]);
            char** argList;
            memcpy(argList,argArray,i);
            execvp(argArray[0],argArray);            
        }
        if((pid = @L_607_18@) == 0) {
            dup2(fds[PIPE_READ],0);
            close(fds[PIPE_READ]);
            close(fds[PIPE_WRITE]);
            execvp(argArraY[i+1],pA);            
        }
        close(fds[PIPE_READ]);
        close(fds[PIPE_WRITE]);
        wait(null);
        wait(null);
        printf("|\n");
    }
    else { 
        if(pid == 0){
            execvp(argArray[0],argArray);
            printf("Command not found.\n");
        }
        else
            wait(null);*/
    }
    *pA++;
    i++;
  }
}

int main () {

  char path[MAX_PATH_LENGTH];
  char buf[BUF_LENGTH];
  char* strArraY[BUF_LENGTH];
  /**
   * "Welcome" message. When mash is executed,the current working directory
   * is displayed followed by >. For example,if user is in /usr/lib/,then
   * mash will display :
   *      /usr/lib/> 
   **/
  getcwd(path,MAX_PATH_LENGTH);
  printf("%s> ",path);
  fflush(stdout);

  /**
   * Loop infinitely while waiTing for input from user.
   * Parse input and display "welcome" message again.
   **/ 
  while(1) {
    fgets(buf,BUF_LENGTH,stdin);
    char *tokenPtr = NULL;
    int i = 0;
    tokenPtr = strtok(buf,delims);

    if(strcmp(tokenPtr,"exit") == 0){

        exit(0);
    }
    else if(strcmp(tokenPtr,"cd") == 0){
        tokenPtr = strtok(NULL,delims);
        if(chdir(tokenPtr) != 0){
            printf("Path not found.\n");
        }
        getcwd(path,MAX_PATH_LENGTH);
    }
    else if(strcmp(tokenPtr,"pwd") == 0){
        printf("%s\n",path);
    }
    else {
        while(tokenPtr != NULL) {
            strArraY[i++] = tokenPtr;
            tokenPtr = strtok(NULL,delims);
        }
        execute(strArray);
    }

    bzero(strArray,sizeof(strArray)); // clears array
    printf("%s> ",path);
    fflush(stdout);
  }

}