Let's try it. The output of the 'ls' command was routed to a file named 'list' and the 'more' command displayed the contents of the file. Some Unix systems will just overwrite the existing file with new information. Others will say 'File exists' and cause the command to fail. The output of the most recent 'ls' command has been appended to the original file, which means the information is added to the bottom of the file.
Some commands expect input to be typed from the keyboard.
Sometimes you would like to take the output of one command and use it as input for a subsequent command. Let's assume that you would like to know how many files you have in a directory. However, Unix has provided a simpler way. The output of the ls command became the input to the 'wc' command. You can extend the pipeline across the page.