Learn Linux Shell Scripting - Fundamentals of Bash 4.4

Binding stdout to stdin

Yes, that is really all that happens. It might be a little disappointing, now that you know all about input and output redirection. However, just because the concept is simple, that doesn't mean that pipes are not extremely powerful and very widely used.

Let's look at an example that shows how we can replace input/output redirection with a pipe:

reader@ubuntu:/tmp$ echo 'Fly into the distance' > filereader@ubuntu:/tmp$ grep 'distance' < fileFly into the distancereader@ubuntu:/tmp$ echo 'Fly into the distance' | grep 'distance'Fly into the distance

For the normal redirection, we first write some text to a file (using output redirection), which we then use as input for grep. Next, we do the exact same functional thing, ...