grep and hard disk access

[Lukul]

Hi everyone,

I have to execute some computations which produce a high amount of output. I want to redirect the output to some file. So I did

./script > output.txt

Now the system administrator complaint that I produce too much hard disk accesses. So I changed my command to

./script | grep [some expression] > output.txt

The expression that grep filters out is only about 10 lines. My question now is: Did I get it right that except the 10 lines, no hard disk access takes place? Or is it possible that the pipe involves some temporal storage of data on parts of the hard disk?

And, is there some way to observe hard disk accesses as non-super user?

Thank you,

Lukul

[hazel]

The expression that grep filters out is only about 10 lines. My question now is: Did I get it right that except the 10 lines, no hard disk access takes place? Or is it possible that the pipe involves some temporal storage of data on parts of the hard disk?

No, in Linux pipes go through the kernel directly from one program to another. DOS used to have a pipe facility that involved one program creating a temporary file which the other program then read and deleted, but that was because DOS could only run one program at a time.

[Lukul]

Thank you. And good to know that thing about DOS