slip25_2.c

#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/types.h>
#include <sys/wait.h>
 #define MAX_LINE 1024
 #define MAX_TOKENS 64
 void tokenize(char *line, char *tokens[]) {
    int i = 0;
    char *token = strtok(line, " \t\n");
    while (token != NULL && i < MAX_TOKENS) {
        tokens[i++] = token;
        token = strtok(NULL, " \t\n");
    }
    tokens[i] = NULL;
 }
 void execute_command(char *tokens[]) {
    pid_t pid = fork();
    if (pid < 0) {
        perror("fork");
        exit(1);
    }
    if (pid == 0) { // Child process
        execvp(tokens[0], tokens);
        perror("execvp");
        exit(1);
    } else { // Parent process
        wait(NULL);
    }
 }
 void search_command(char *filename, char *pattern) {
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        perror("fopen");
        return;
    }
    char line[MAX_LINE];
    while (fgets(line, MAX_LINE, fp) != NULL) {
        if (strstr(line, pattern) != NULL) {
            printf("%s", line);
            break;
        }
    }
    fclose(fp);
 }
 int main() {
    char line[MAX_LINE];
    char *tokens[MAX_TOKENS];
    while (1) {
        printf("myshell$ ");
        fflush(stdout);
        fgets(line, MAX_LINE, stdin);
        tokenize(line, tokens);
        if (strcmp(tokens[0], "search") == 0) {
            if (tokens[1] != NULL && tokens[2] != NULL) {
                search_command(tokens[1], tokens[2]);
            } else {
                printf("Usage: search <filename> <pattern>\n");
            }
        } else {
            execute_command(tokens);
        }
    }
    return 0;
}