Python | os.ftruncate() method Improve Improve Like Article Like Save Share Report OS module in Python provides functions for interacting with the operating system. OS comes under Python’s standard utility modules. This module provides a portable way of using operating system dependent functionality. os.ftruncate() method truncates the file corresponding to file descriptor fd, so that it is at most length bytes in size. Syntax: os.ftruncate(fd, length) Parameters: fd: This is the file descriptor that is to be truncated. length: This is the length of the file upto which file is to be truncated. Return Value: This method does not returns any value. Example #1 : Using os.ftruncate() method to truncate a file # Python program to explain os.ftruncate() method # importing os module import os # path path = 'C:/Users/Rajnish/Desktop/testfile.txt' # Open the file and get # the file descriptor associated # with it using os.open() method fd = os.open(path, os.O_RDWR|os.O_CREAT) # String to be written s = 'GeeksforGeeks' # Convert the string to bytes line = str.encode(s) # Write the bytestring to the file # associated with the file # descriptor fd os.write(fd, line) # Using os.ftruncate() method os.ftruncate(fd, 5) # Seek the file from beginning # using os.lseek() method os.lseek(fd, 0, 0) # Read the file s = os.read(fd, 15) # Print string print(s) # Close the file descriptor os.close(fd) Output: b'Geeks' Example #2 : Using os.ftruncate() method to truncate a file # Python program to explain os.ftruncate() method # importing os module import os # path path = 'C:/Users/Rajnish/Desktop/testfile.txt' # Open the file and get # the file descriptor associated # with it using os.open() method fd = os.open(path, os.O_RDWR|os.O_CREAT) # String to be written s = 'GeeksforGeeks - Computer Science portal' # Convert the string to bytes line = str.encode(s) # Write the bytestring to the file # associated with the file # descriptor fd os.write(fd, line) # Using os.ftruncate() method os.ftruncate(fd, 10) # Seek the file from beginning # using os.lseek() method os.lseek(fd, 0, 0) # Read the file s = os.read(fd, 15) # Print string print(s) # Close the file descriptor os.close(fd) Output: b'GeeksforGe' Last Updated : 25 Jun, 2019 Like Article Save Article Previous Python | os.umask() method Next Python | os.getcwd() method Share your thoughts in the comments Add Your Comment Please Login to comment... Similar Reads Class Method vs Static Method vs Instance Method in Python Class method vs Static method in Python Difference between Method Overloading and Method Overriding in Python Pandas DataFrame iterrows() Method | Pandas Method Pandas DataFrame interpolate() Method | Pandas Method Pandas DataFrame duplicated() Method | Pandas Method Python Dictionary get() Method Real-Time Edge Detection using OpenCV in Python | Canny edge detection method Python | os._exit() method Python | os.WEXITSTATUS() method Like R Rajnis09 Follow Article Tags : python-os-module Python Practice Tags : python