Not only can you redirect standard output, you can perform the same type of redirection with standard input.
Here's how it works:
When you use the redirect standard input symbol <, you're telling the shell that you want a file to be read as input for a command.
We can use a file we've already created to demonstrate this idea. Just type:
cat < sneakers.txt
Because we used the less-than symbol (<) to separate the cat command from the file, the output of sneakers.txt was read by cat.