how to backup the oracle 10 database using expdp

to backup the database using expdp:
cd ~/path/to/oracle/product/10.2.0/db_1/bin
./sqlplus "sys/any as sysdba"
SQL> startup;
SQL> exit;
./lsnrctl start
./sqlplus "sys/any as sysdba"

if you already havent done so:
SQL> grant read, write on directory DATA_PUMP_DIR to scott;

now run:

SQL> host


$ ./expdp scott/mypassword DIRECTORY=DATA_PUMP_DIR DUMPFILE=expdat_scott.dmp

the backup dmp file will be here:
/path/to/oracle/product/10.2.0/db_1/rdbms/log/

which is the default value/location for DATA_PUMP_DIR

you can double check it in sqlplus like this:
SQL> SELECT directory_path FROM dba_directories WHERE directory_name = 'DATA_PUMP_DIR';

source: http://www.orafaq.com/wiki/Datapump