Mysql import multiple CSV and SQL from a folder - mysql

Question

First of all, my initial intention is simply want to rename/copy a database. But the thrist of knowledge is extending a little further.
I knew about mysqldump db | mysql db. I also knew about LOAD LOCAL DATA INFILE to import a single CSV.
Mysql has a nice way to dump a DB as CSV into a single folder
mysqldump -T/some/folder db
Now that folder will contain both SQL and TXT files for each table (table1.sql, table1.txt, ...)
Why I'm choosing this method is because I have a database with 4Gb size, and using the traditionnal import is painfully slow. I heard that using CSV import might give a better performance.
Questions :
Is there any official way to do the reverse operation, which read from a folder that contains both SQL and TXT files?
Does exporting like this then import ensure an exact copy of the original DB? (indexes, primaries, uniques, views, etc...)
EDIT:
So I did some research.
Not the best way but it's from official doc to do the reverse operation https://dev.mysql.com/doc/refman/5.7/en/reloading-delimited-text-dumps.html (O.Jones'answer)
If we loop over the folder and import files one by one order alphabetically, we'll eventually run into InnoDB key constraints problem. Disable key check seems not solving the problem.
Quite a MYTH but mysqldump with --opt then import SQL seems import faster than CSV due to many optimizations! The command used is mysqlimport and not LOAD DATA INFILE (I will try later to see if there is any difference)

Answer 1

This is a little late, but there's a small trick you can do with bash.
cd to the folder where the files are and:
for x in $(ls *.txt); do mysqlimport -u YOURUSER -pYOURPASS --local database_to_import_into $x;done
this will do the trick.