Delimited by comma using AWK or SED with the tags below

Question

Delimited by comma using AWK or SED with the tags used below:

[BEGIN AccountID]
        [BEGIN CallerID]
            [BEGIN Billed Account Attributes]
                   


        

Answer 1

This might work for you (GNU sed):

sed '/\[BEGIN AccountID\]/,/\[END AccountID\]/!d;/\[BEGIN AccountID\]/{h;d};/./H;/\[END AccountID\]/!d;g;s/\n*\[[^\n]*\n*//g;s/\n/,/g;s/\s*//g;ta;:a;s/,//9;t;s/$/0,0,0/' file

N.B. This removes spaces and blank lines.