myid.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void get_user_info(char *username) {
    FILE *fp = fopen("/etc/passwd", "r");
    if (fp == NULL) {
        perror("Cannot open /etc/passwd");
        return;
    }

    char line[256];
    int found = 0;
    while (fgets(line, sizeof(line), fp)) {
        // /etc/passwd: username:password:UID:GID:info:home:shell
        char *token = strtok(line, ":");
        if (token != NULL && strcmp(token, username) == 0) {
            found = 1;
            char *pass = strtok(NULL, ":");
            char *uid = strtok(NULL, ":");
            char *gid = strtok(NULL, ":");
            char *info = strtok(NULL, ":");
            char *home = strtok(NULL, ":");
            char *shell = strtok(NULL, ":");

            printf("User: %s\n", username);
            printf("UID: %s\n", uid);
            printf("GID: %s\n", gid);
            printf("Home: %s\n", home);
            break;
        }
    }

    if (!found) printf("User not found!\n");
    fclose(fp);
}

int main() {
    char username[50];
    printf("Enter username: ");
    scanf("%s", username);
    get_user_info(username);
    return 0;
}