FIFOs

• A first-in, first-out (FIFO) file is a pipe that has a name in the filesystem.
• Any process can open or close the FIFO; the processes on either end of the pipe need not be related to each other.
• FIFOs are also called named pipes.

  $ mkfifo /tmp/fifo 
  $ ls -l /tmp/fifo
  

• In one window, read from the FIFO by invoking the following:

  $ cat < /tmp/fifo
  

• In a second window, write to the FIFO by invoking this:

  $ cat > /tmp/fifo
  

• Then type in some lines of text. Each time you press Enter, the line of text is sent through the FIFO and appears in the first window. Close the FIFO by pressing Ctrl+D in the second window.
• Remove the FIFO with this line:

  $ rm /tmp/fifo