Guide: Simple File Operations

To manipulate the file (read its contents, modify them, change its size etc.), each process must first get a handler to this file. Think of this handler as an object by which the process can identify and refer to the file.

Now take a look at the code examples in file-descriptors/guides/simple-file-operations/support. Each of them reads the contents of file.txt, modifies them, and then reads the previously modified file again. Use make to compile the C code, and make java-file-operations to compile the Java code.

Now run the programs repeatedly in whatever order you wish:

student@os:~/.../simple-file-operations/support$ python3 file_operations.py
File contents are: OS Rullz!
Wrote new data to file
File contents are: Python was here!

student@os:~/.../simple-file-operations/support$ ./file_operations  # from the C code
File contents are: Python was here!
Wrote new data to file
File contents are: C was here!

student@os:~/.../simple-file-operations/support$ java FileOperations
File contents are: Python was here!
Wrote new data to file
File contents are: Java was here!

Note that each piece of code creates a variable, which is then used as a handler.

Quiz