How can I import a database using command line?

I believe the format is:

mysql -u username -p database_name < /path/to/file.sql

From within mysql:

mysql> use db_name;
mysql> source backup-file.sql;

The main problem is that you're trying to run a bash command from within mysql. If you run that command at the regular terminal prompt the format of the command is correct.

The second issue is that you have a zip file and not a SQL file so you need to unzip it first.

How do I load a sql.gz file to my database? (on Server Fault) explains most of what you need. My answer there should work here too with a slight modification:

unzip -p /var/www/backup.zip | mysql -u root -p mydb

unzip -p unzips to a pipe, so that you can pipe that into your database command. Make sure the zip file only contains one sql file.

mysql -u root -p mydb is going to prompt you for a password (the -p without a value) and then attempt to pipe in the file data to mydb - change the mydb to your own database. You shouldn't specify the password in the command line as it then remains in your command history.