1.
Fork System Call program
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h> // Include this header for fork(), getpid(), and getppid()
int main() {
int pid;
pid = fork(); // Fork system call
// Check if fork() failed
if (pid == -1) {
printf("\n CHILD PROCESS NOT CREATED\n");
exit(0); // Exit if fork fails
// If we're in the child process
if (pid == 0) {
printf("\n I AM CHILD PROCESS AND MY ID IS %d\n", getpid());
printf("\n THE CHILD PARENT PROCESS ID IS: %d\n", getppid());
// If we're in the parent process
else {
printf("\nI AM PARENT PROCESS AND MY ID IS %d\n", getpid());
printf("\nTHE PARENTS PARENT PROCESS ID IS: %d\n", getppid());
return 0;
}
2. System call with arguments program
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h> // For fork and execvp
int main(int argc, char *argv[]) {
int pid, i;
pid = fork();
if (pid == -1) {
// Fork failed
printf("\n CHILD PROCESS NOT CREATED\n");
exit(1);
if (pid == 0) {
// Child process code
printf("\n CHILD PROCESS IS IN PROGRESS\n");
for (i = 0; i < 5; i++) {
printf("\n THE CHILD PROCESSING VALUE IS: %d\n", i);
execvp("ls", argv); // Executes 'ls' command
// execvp replaces the current process image, so anything after this line won't be executed unless
execvp fails.
printf("\n EXECVP FAILED\n");
exit(0);
} else {
// Parent process code
printf("\n PARENT PROCESS IS WAITING\n");
// You can add wait() here to wait for the child process to finish.
wait(NULL);
printf("\n CHILD PROCESS COMPLETED ITS TASK\n");
return 0;
3. Working with directory program
#include <stdio.h>
#include <stdlib.h>
#include <dirent.h> // Correct header for directory operations
int main(int argc, char *argv[]) {
DIR *dir;
struct dirent *rddir;
// Check if directory argument is provided
if (argc != 2) {
printf("Usage: %s <directory_name>\n", argv[0]);
exit(1); // Exit if directory path is not provided
printf("LISTING THE DIRECTORY CONTENT\n");
// Open the directory
dir = opendir(argv[1]);
if (dir == NULL) {
perror("opendir"); // Print error if directory can't be opened
exit(1);
printf("THE CURRENT DIRECTORY FILES ARE:\n");
// Loop through directory entries and print them
while ((rddir = readdir(dir)) != NULL) {
printf("%s\n", rddir->d_name); // Print each file's name
closedir(dir); // Close the directory once done
return 0; // Return 0 to indicate successful execution
4. Stat system call program
#include <stdio.h> // For printf, perror
#include <sys/types.h> // For stat struct types
#include <sys/stat.h> // For struct stat
#include <time.h> // For ctime()
int main() {
struct stat sfile;
// Replace "stat.c" with the file you want to check
if (stat("stat.c", &sfile) == -1) {
perror("stat"); // If stat() fails, print the error
return 1; // Return an error code
// Print file information
printf("File Owner UID: %d\n", sfile.st_uid); // User ID
printf("File Owner GID: %d\n", sfile.st_gid); // Group ID
printf("File Size: %lld bytes\n", (long long) sfile.st_size); // File size
printf("File Blocks: %lld\n", (long long) sfile.st_blocks); // Blocks allocated
printf("File Inode Number: %ld\n", sfile.st_ino); // Inode number
// Convert timestamps to readable format
printf("Last Access Time: %s", ctime(&sfile.st_atime)); // Last accessed
printf("Last Modification Time: %s", ctime(&sfile.st_mtime)); // Last modified
printf("Last Status Change Time: %s", ctime(&sfile.st_ctime)); // Metadata change
return 0; // Success
