Python 3 - Method


The method read() reads at most n bytes from file desciptor fd, return a string containing the bytes read. If the end of file referred to by fd has been reached, an empty string is returned.

Note − This function is intended for low-level I/O and must be applied to a file descriptor as returned by or pipe(). To read a “file object” returned by the built-in function open() or by popen() or fdopen(), or sys.stdin, use its read() or readline() methods.


Following is the syntax for read() method −,n)


  • fd − This is the file descriptor of the file.

  • n − These are n bytes from file descriptor fd.

Return Value

This method returns a string containing the bytes read.


The following example shows the usage of read() method.

# !/usr/bin/python3
import os, sys

# Open a file
fd ="foo.txt",os.O_RDWR)
# Reading text
ret =,12)
print (ret.decode())

# Close opened file
print ("Closed the file successfully!!")


Let us compile and run the above program, this will print the contents of file foo.txt

This is test
Closed the file successfully!!