Pipeline "|" versus output redirection ">"


#1

Question

The uses of output redirection, >, and pipelining, |, seem similar. What is the distinction in their use?

Answer

The distinction here is between storage and use as input. Consider the following example

cat volcanoes.txt | wc

from this lesson. Here we’re using the result of the left side, cat volcanoes.txt, as input to the right side, wc. If we instead wrote

cat volcanoes.txt > wc

then we would use the result of the left side and store it into a file called wc. This is a very different behavior than what we did with | above.


FAQ: Redirection - |
#2

I was confused by this lesson:
$ cat volcanoes.txt | wc | cat > islands.txt

if we want to “pipe” the standard output of volcanoes.txt to islands.txt, could we write
$ cat volcanoes.txt | wc > islands.txt ? cat islands.txt turns out the same result as the lesson.

And please explain to me what the difference between storage and use as input?


#3

I’m confused about this as well. Could someone help plz?