Python os.isatty() Method

1. Syntax of Python os.isatty() Method
2. Example 1: Use the os.isatty() Method to Check if File Descriptor Is Open and Connected to tty(-like) Device
3. Example 2: Create a New File and Use the os.isatty() Method

Python os.isatty() method is an efficient way of checking whether a specified file descriptor (fd) is open or not and connected to a tty(-like) device. The tty(-like) device means any device that can act like a teletype, i.e., a terminal.

Syntax of Python os.isatty() Method

os.isatty(fd)

Parameters

Return

The return type of this method is a Boolean value. The Boolean value True is returned if the specified fd is open and connected to any tty(-like) device; otherwise, False is returned.

Example 1: Use the os.isatty() Method to Check if File Descriptor Is Open and Connected to tty(-like) Device

import os

r, w = os.pipe()

print("Is it connected to a 'tty(-like)' device or a terminal?: ", os.isatty(r))

master, slave = os.openpty()

print("Is it connected to a 'tty(-like)' device or a terminal?: ", os.isatty(master))

Output:

Is it connected to a 'tty(-like)' device or a terminal?:  False
Is it connected to a 'tty(-like)' device or a terminal?:  True

We open a new pseudo-terminal pair in the above code using the os.openpty() method. It will return us a master and slave pair file descriptor, and we then use the os.isatty() method to check if it can connect to a terminal or not.

Example 2: Create a New File and Use the os.isatty() Method

import os

fd = os.open( "File.txt", os.O_RDWR|os.O_CREAT )

os.write(fd, 'Hello, World!'.encode())

terminal = os.isatty(fd)

print ("Is it connected to a 'tty(-like)' device or a terminal?", terminal)

os.close(fd)

Output:

Is it connected to a 'tty(-like)' device or a terminal? False

A file’s fd is an integer value corresponding to resources, like a pipe or network socket.