Question : Need help building a regex

I have a file that's around 80GiB that I need to manipulate. Initially I made a vim macro to handle my problem, but that's not near fast enough to process such an amount of data.

sed or an equivalent can probably do this much much faster.

Here's some pseudo code for what I need:
startString="Some text here"
Find each line that begins with startString
For each line, find the sixth ,
The comma will be followed by a '' enclosed string, replace the string, including the 's with NULL.

Answer : Need help building a regex

Something like this perhaps?

                       
             find / -name "*.html" -exec for file in `grep -l host.something.com {} \;`; do; lines=`wc -l $file | cut -f 1 -d' '`; keep=$[lines-2]; head -$keep $file.new; done

Question : Need help building a regex

Answer : Need help building a regex

Something like this perhaps? 1: find / -name "*.html" -exec for file in `grep -l host.something.com {} \;`; do; lines=`wc -l $file | cut -f 1 -d' '`; keep=$[lines-2]; head -$keep $file.new; done

Something like this perhaps?

1:

find / -name "*.html" -exec for file in `grep -l host.something.com {} \;`; do; lines=`wc -l $file | cut -f 1 -d' '`; keep=$[lines-2]; head -$keep $file.new; done