stdin is:exact
stdin is a handle managing the programs standard input.
A handle managing input from the Haskell program's standard input
channel.
sourceHandle applied to stdin.
Subject to fusion
Read chunks of bytes from standard input
The chunks are not necessarily aligned to line boundaries
Read lines of
Text from standard input
Read input query from stdin
Source from stdin, yielding bytestrings as they are drawn. If you want
to retrieve each line as a string, see
stdinLines.