You can combine files based on more than one key. The files must contain the
same data format, and the key data items must start at the same character
position (column) and be the same length.
To combine EMPLOYEE and NEWHIRES into a new file named
COMPANY by last name, first name, and job title, enter the following
sequence of commands:
This would arrange the two CARLSON entries in their proper
alphabetical order with regard to their first names. Only the two
CARLSON entries are shown in the following example: