You can import .sql file using :
mysql -u <user> -p<password> <dbname> < mysqlfile.sql
Note: There shouldn't space between -p and <password>
Reference: http://dev.mysql.com/doc/refman/5.0/en/mysql-batch-commands.html
Time taken for importing huge files most importantly it takes more time is because default setting of mysql is "autocommit = true", you must set that off before importing your file.
First open MySQL:
mysql -u root -p
Then, You just need to do following :
mysql>use your_db
mysql>SET autocommit=0 ; source the_sql_file.sql ; COMMIT ;