Rename a File using C

To rename a file using C, you can use the rename() function from stdio.h, or the system() function.

Example 1: Renaming a File using rename() Function

In this example, we will rename a file named oldfile.txt to newfile.txt using the standard rename() function. This function is part of stdio.h and is straightforward for renaming files in C.

main.c

</>
Copy
#include <stdio.h>

int main() {
    // Attempt to rename the file "oldfile.txt" to "newfile.txt"
    if (rename("oldfile.txt", "newfile.txt") != 0) {
        perror("Error renaming file");
    } else {
        printf("File renamed successfully.\n");
    }
    return 0;
}

Explanation:

  1. The rename() function is called with two arguments: the current filename "oldfile.txt" and the new filename "newfile.txt".
  2. The if statement checks whether the rename() function returns a non-zero value, which indicates an error.
  3. If an error occurs, perror() prints an error message explaining the issue.
  4. If the operation is successful, printf() outputs a success message.

Output:

File renamed successfully.

Example 2: Renaming a File using the system() Function

In this example, we use the system() function to execute a shell command that renames a file. This approach can be useful in environments where you want to leverage shell commands, though it is less portable than using rename().

main.c

</>
Copy
#include <stdio.h>
#include <stdlib.h>

int main() {
    // Using system() to rename a file via shell command (works on Unix-like systems)
    int status = system("mv oldfile.txt newfile.txt");
    if (status != 0) {
        printf("Error renaming file using system call.\n");
    } else {
        printf("File renamed successfully using system call.\n");
    }
    return 0;
}

Explanation:

  1. We include stdlib.h to use the system() function.
  2. The system() function executes the shell command "mv oldfile.txt newfile.txt", which renames the file on Unix-like systems.
  3. The returned value is stored in the variable status, which is checked for errors. A non-zero value indicates a failure.
  4. If the renaming fails, an error message is printed using printf(). Otherwise, a success message is printed.

Output:

File renamed successfully using system call.

Conclusion

This tutorial demonstrated two different approaches to rename a file using C:

  1. rename() Function: A standard and portable way to rename files, which provides error checking using perror().
  2. system() Function: Executes a shell command (mv on Unix-like systems) to rename the file, useful in specific environments.