Slightly modify the control file ... add the column length where needed.
Let's say, for example, that your control file looks like this:
Code:
LOAD DATA
INFILE some_file.txt
INTO TABLE your_table
(column_name POSITION(001:010) CHAR)
When loading, you'll lose trailing blanks. To prevent this to happen, the last row in example control file should look like this:
Code:
(column_name POSITION(001:010) CHAR(10))
P.S. I guess it is about Oracle SQL*Loader utility ... if so, I'd suggest you to post questions regarding Oracle in the Oracle forum.