[takawa]

Some commands output (e.g netstat) seem to have non standard format. It is for the purpose of extracting data automatically that I am inquiring. Is there some spec for this output? some clarification please. Thank you.

[fishsponge]

what sort of "spec" are you looking for?

All commands output text of some sort, but there is (and never will be) no specific format that they all follow. Each command's output is different.

[takawa]

Thank you for reply. I thought this area (shells scripting) is more appropriate.
What I mean is that, in output, there's no hard fixed presentation of fields and parts of the text. If I want to extract data through grep, sed..,it is difficult or unfeasibe. The remaining question is that are they all ASCII? Line breaks are newline character, tabs,..? Thank you.

[fishsponge]

ah, ok - i believe that all output to a terminal is indeed ASCII (basic text). Line breaks probably are a newline character, and tabs probably are a tab character.

What is it you are trying to extract - you don't normally need to go into this level of depth to grab some values from a command's output...