Exporting table content using a transport of copies is sometimes used to export table data out of a SAP system before the database is refreshed. Once the database is refreshed the transport request is imported again to insert the entries back into the table. There are other means of exporting table data of course but some tables cannot be exported using the EXP or BR*Tools from Oracle for example so this can come in handy.
*EDIT Note that using Oracle EXP seperately is not supported by SAP so I don’t recommend you start using EXP.
Go to transaction SE01
Click on Request à \ Create
Select Transport of copies
Provide a short description for your transport request
Enter the SID of your SAP system in the Target field
Now double-click the Request <SID>K90043 (for example) \ under the header Modifiable
Click on the Pencil icon to go into change mode
Now insert R3TR TABU into Pro Obj columns
Insert the name of the table you wish to export in the \ Object Name column
Now click on the key Icon next to the Object Name column
If you want to export the full table content insert a * into \ the Table Keys field
If you now go back into transaction SE01 you will notice the \ Table Contents appearing under the transport request.
Place your cursor on the transport request and push the \ release button to release the transport request. At that moment the table data \ will be exported into the transport request.
Once the transport request is released (and the release \ finished successfully) you should see the data- and cofile of this transport \ request in your transport directory. You can then use the transport request to \ import the table data again at a later points in time (after a database refresh \ for example).