«Redirecting Input and Output» 8/13: What's the difference between …

$ sort lakes.txt 


$ cat lakes.txt | sort


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in the first you sort the content of the lakes.txt, in the second code sample you pipe the standard output of the file to sort

this enables us to for example do a grep first:

cat lakes.txt | grep lake | sort

so sort anything with lake in the name.


thanks. I get your explanation but still it does not really make sense to me.
wouldn’t your code be the same as:

sort lakes.txt | grep lake


the output, maybe, yes. But now we first have to sort everything, and then pipe that output to grep and grep the entries we want. Sound less efficient. Sorting is generally an expensive operation.

also, it will happen that you might have 5 pipes, or a file with 100,000 lines

the big problem is that these “commands” are entire programs written in the C language. Due to this abstraction, it might be difficult to “see” the difference.


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Oops, the topic closed automatically, did you still want to reply something?

no, thanks a lot for your help! :ok_hand:

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