Implement a Python script that reads standard input (stdin) and writes to standard output (stdout).
Write a function that reads all lines from standard input, performs a transformation on each line, and writes each line to standard output.
Write several functions that either filter or transform a single line. This function should take one argument (a string). It should return a string or None (if the line is to be skipped).
Here are a few possible filters:
Here are a few possible transformations:
Pass your single-line function to the function that reads from standard input and writes to standard output.
What you will learn: