Python | os.isatty() method

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.isatty() method in Python is used to check whether the specified file descriptor is open and connected to a tty(-like) device or not. “tty” originally meant “teletype” and tty(-like) device is any device that acts like a teletype, i.e a terminal.

A file descriptor is small integer value that corresponds to a file or other input/output resource, such as a pipe or network socket. It is an abstract indicator of a resource and act as handle to perform various lower level I/O operations like read, write, send etc.

Syntax: os.isatty(fd)

Parameter:
fd: A file descriptor, whose is to be checked.

Return Type: This method returns a Boolean value of class bool. Returns True if the specified file descriptor is open and connected to a tty(-like) device otherwise, returns False.

Code: Use of os.isatty() method to check if the given file descriptor is open and connected to tty(-like) device or not

# Python program to explain os.isatty() method

# importing os module
import os


# Create a pipe using os.pipe() method
# It will return a pair of
# file descriptors (r, w) usable for
# reading and writing, respectively.
r, w = os.pipe()


# Check if file descriptor r
# is open and connected
# to a tty(-like) device
# using os.isatty() method
print("Connected to a terminal:", os.isatty(r))



# Open a new pseudo-terminal pair
# using os.openpty() method
# It will return master and slave
# file descriptor for
# pty ( pseudo terminal device) and
# tty ( native terminal device) respectively
master, slave = os.openpty()

# Check if file descriptor master
# is open and connected
# to a tty(-like) device
# using os.isatty() method
print("Connected to a terminal:", os.isatty(master))

Output:

Connected to a terminal: False
Connected to a terminal: True