mysql restore specific date data from a dump file
You have two alternatives:

1. Load the file into a new database table and do a query for the particular date that you want.

or 

2. Hand edit the dump file and load that (also in a new database).

The second alternative has several disadvantages:


hand editing is unreliable and error prone.
you may break integrity constraints - not easy to see in a load of text!
it's a pain in the ass :-) and will probably take you more time than alternative 1.


Conclusion:

Load the whole file - query the data you want,

CREATE my_table AS SELECT * FROM main_table
WHERE the_date = date_of_interest;


and then put that into a separate table, and then:

mysqldump db_name my_table &gt; my_table.sql


Et voilà!