In Linux, the pipe command lets you sends the output of one command to another. Piping, as the term suggests, can redirect the standard output, input, or error of one process to another for further processing.
The syntax for the pipe or unnamed pipe command is the | character between any two commands:
Command-1 | Command-2 | …| Command-N
Here, the pipe cannot be accessed via another session; it is created temporarily to accommodate the execution of Command-1 and redirect the standard output. It is deleted after successful execution.
contents.txt contains a list of all files in a particular directory—specifically, the output of the ls -al command. We first grep the filenames with the "file" keyword from contents.txt by piping (as shown), so the output of the cat command is provided as the input for the grep command. Next, we add piping to execute the awk command, which displays the 9th column from the filtered output from the grep command. We can also count the number of rows in contents.txt using the wc -l command.
A named pipe can last until as long as the system is up and running or until it is deleted. It is a special file that follows the FIFO[1] (first in, first out) mechanism. It can be used just like a normal file; i.e., you can write to it, read from it, and open or close it. To create a named pipe, the command is:
mkfifo <pipe-name>This creates a named pipe file that