Pipes are a fundamental inter-process communication mechanism on operating systems. They enable the output of one process to be redirected to another. When you write a command on the terminal, the shell is actually creating a process that can execute your command. Since pipes are used to glue together different processes, you can also use pipes on the terminal to enable communication between different commands. The pipe command, represented as a bar symbol |, lets you transfer the output of one command as the input of the next.