sysstdin

sys.stdin is a standard component of Python’s runtime that represents the program’s standard input stream. It is exposed via the sys module as a global, file-like object that can be read from just as a file. In CPython, sys.stdin is a TextIOWrapper around a buffered binary stream, providing a convenient text interface for reading text data. Its text encoding is typically derived from the system locale and is accessible through attributes like sys.stdin.encoding; many aspects of its behavior can be adjusted in modern Python versions using reconfigure.

As a text stream, sys.stdin supports common file-like operations such as read, readline, and readlines, and it is also iterable line by line. The built-in input() function reads a line from sys.stdin, strips the trailing newline, and returns it as a string. For binary data, the underlying raw buffer can be accessed via sys.stdin.buffer, which provides a binary interface separate from the text wrapper.

Usage and behavior: sys.stdin reads data supplied to the program from the console, a redirected file, or a piped command. When input is redirected (for example, program < file.txt or a pipe from another process), sys.stdin reads from that source instead of a terminal. environments such as integrated development environments or notebooks may alter or stub sys.stdin, affecting how input is received.

Reassignment and compatibility: sys.stdin is a global resource and can be reassigned to another file-like object, though doing so can affect other parts of the program. For text processing, rely on sys.stdin for reading input data and consider sys.stdin.buffer for raw bytes.