Example 3-5: Simple pipelines.

Some examples of simple pipes:

ls -al | more

Produce a long listing of all files in the current directory, and pass the output into the “more” command so that it will be displayed only one page at a time on the computer screen.

ps -ef | more

Create a full listing of every process running on the computer, and allow the “more” command to control the output as it is displayed on your screen.

who | wc -l

Pipe the output of the who command into the input of the wc -l command (this counts the number of lines of input).  This tells you the number of users currently logged in.