emacs: Search/ReplaceAll :Regex

[no.to...@gmail.com]

Obviously emacs can Search/ReplaceAll forward TextBlocks.
And withRegex; like "[7]" equivalent to "[492]", and ignore
blank-lines, and ignore space & tabs.

Whereas most editors can't handle 50-lines [4000 chars];
probably emacs can ?

Since I've only got slight experience of emacs from years ago,
I don't want to open a canOworms and find that emacs can't
easily achieve my goal. So I'm asking for confirmation and possible
pointers.
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If you want to know the application:--
The application is one that others should have found long ago.
These days if you want info, you shouldn't use a graphical-browser.
Information comes in TEXT.
After you've got a google-provided list of leads, you start downloading
the pages, to read and search for your answers.

For serious research, you append the pages to a file: creating a book.
I use a separator-line between appends, thus: "<><><><>"

Unfortunately ALL web-pages from the same 'base' have the same
REPEATED packaging for EACH web-page. This is what you want
emacs to Search and replace/delete.

Often the repeated/packaging is ten-times-bigger than the
relevant information. So if you don't delete it, it becomes distracting
noise, when you read the file to try to understand the valuable info.

It's a bit like those gadgets which clean-out-the-TV-commercials.

== TIA.