Shell

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>

#define MAX_LENGTH 1024
#define DELIMS " \t\r\n"

int main(int argc, char *argv[]) {
    call_func(stdin);
    return 0;
}

void call_func(FILE *stream) {
    char *cmd;
    char *line;
    char cwd[MAX_LENGTH];
    char** commands;
    char commands_args[MAX_LENGTH];

    while(1) {
        errno = 0;
        if (getcwd(cwd, sizeof(cwd)) != NULL) {
            fprintf(stdout, "%s $ ", cwd);
        }

        else {
            perror("getcwd() error");
        }

        line = malloc(100 * sizeof(char));

        if (!fgets(line, MAX_LENGTH, stream)) {
            break;
        }
        line = strtok(line, "\n");
        commands = (char**)malloc(50 * sizeof(char*));
        for (int i = 0; i < 50; i++) {
            commands[i] = (char*)malloc(50 * sizeof(char));
        }
        if((commands[0] = strtok(line, "|"))) {
            int i = 1;
            while(1) {
                commands[i] = strtok(0, "|");
                if(commands[i] == NULL) {
                    break;
                }
            }
            if((cmd = strtok(commands[0], " "))) {
                if (strcmp(cmd, "cd") == 0) {
                    char *arg = strtok(0, DELIMS);
                    if (!arg) {
                        fprintf(stderr, "cd missing argument.\n");
                    }

                    else {
                        chdir(arg);
                    }
                }
                else if (strcmp(cmd, "exit") == 0) {
                    break;
                }
                else if (strcmp(cmd, ".") == 0) {
                    char *arg = strtok(0, DELIMS);
                    FILE * pFile;
                    pFile = fopen (arg,"r");
                    call_func(pFile);
                }
                else if (cmd == NULL) {
                    system(line);
                }
                else {
                    int pfds[2];
                    pipe(pfds);
                    int id = fork();
                    if(id == 0) {
                        dup2(pfds[1], 1);
                        close(pfds[0]);
                        char* argb[20];
                        argb[0] = cmd;
                        argb[1] = strtok(0, DELIMS);
                        argb[2] = NULL;
                        execvp(argb[0], argb);
                        exit(o);
                    }
                    else {
                        int id_2 = fork();
                        if(id_2 == 0) {
                            dup2(pfds[0], 0);
                            close(pfds[1]);
                            wait(&id);
                            char* argb[20];
                            argb[0] = "grep";
                            argb[1] = "c";
                            argb[2] = NULL;
                            execvp(argb[0], argb);
                            exit(o);
                        }
                        else {
                            wait(&id);
                            wait(&id_2);
                            printf("done");
                        }
                    }
                }
                if (errno) {
                    perror("Command failed");
                }
            }
        }
    }
}
//Gemaakt door Joeri van Vuuren en Gijs Schrijver