Dear Chris,
Thank you for your polite explanation.
I will read the instruction site about RegEX.
If you really don't recommend Friedl's book do you have any recommended books?
From the age of over 70th, it is much easier for the eyes to see it slowly in the book than to see the characters on the display screen.
Recommended BBEdit.app purchased at the end of last year.
I am currently using it for writing various sentences so that it can be used.
Moreover, I was able to prepare the environment for using LaTex gradually with BBEdit, because I love using LaTeX anyway.
Thx and regards,
WAKAMATSU (boehmflute)