The specification of what you're trying to do is confusing.

Your awk script is using comma as the input field separator, but your sample input file is using spaces (not commas) as field separators. Furthermore, part of your rules in step 4:

Code:

        if the VALUE is "14,385" and COMMENT "d" then NUMB is "14385" and STRING(both) is null
        if the VALUE is "14,385" and COMMENT "du" then NUMB is "14385" and STRING_STATUS is "u"

contains commas in the data in a field. Is that field supposed to be quoted in your input.csv file? If not, you can't have commas that are both data and field separators.

You say that you want tab as the field separator in your output file, but the sample output you have shown us has leading spaces on many of the lines and one or four spaces as field separators. And with headings STRING_COM and STRING_STATUS (both of which are more than eight characters wide), the data won't line up under your output headers. (Could you use COM and STATUS as output heading instead of STRING_COM and STRING_STATUS?

There are several combinations of VALUE and COMMENT listed in rule 4 that are not included in your sample data.

There is nothing in rule 4 that says what should happen if VALUE is neither a colon nor 14,385. Add a case (or cases) to rule 4 to cover all expected input combinations.

Please update your request to make the sample data you provide (both input.csv and output) match your specifications, update rule 4 to cover all possible input, and add sample input and output that tests all of the conditions specified in your updated rule 4.

When your specification of a problem is incomplete and your sample input and output don't match the description of your input and desired output, it is highly likely that you won't get any response to your request for help. When your specifications are clear and your sample data shows the transformations you're trying to perform, you are much more likely to get a quick response.