Comparing Contents of Files

To compare the contents of two files to see if they are identical, use the COMPARE command from the CMS command line. The comparison is made on a record-for-record basis and dissimilar records are displayed to the terminal.

For example, suppose two files exist with the following contents:

EMPLOYEE LIST A        EMPLOYEE LIST B

Kathy                      Kathy
Diana                      Diana
Kate                       Kate

To compare the contents of EMPLOYEE LIST A with EMPLOYEE LIST B, the following command would be entered:
compare employee list a employee list b
The following message would be returned indicating that contents of the files are identical:
DMSCMP179I Comparing EMPLOYEE LIST A with EMPLOYEE LIST B
Ready; T=0.30/0.03 08:06:21
If, in the second file, employee Kate was replaced by new employee Terri, the COMPARE command would return the following:
DMSCMP179I Comparing EMPLOYEE LIST A with EMPLOYEE LIST B
Kate
Terri
DMSCMP209W Files do not compare
Ready(00004); T=0.01/0.01 08:08:15
The line from each file which did not match is displayed.

Since the comparison is done a record-for-record basis, the insertion or deletion of a line may return misleading results. For example, if EMPLOYEE LIST2 A was an identical copy of EMPLOYEE LIST A, and the name of a new employee, Tom, was inserted in the file, so the contents of the files were:

EMPLOYEE LIST A        EMPLOYEE LIST2 A

Kathy                      Tom
Diana                      Kathy
Kate                       Diana
                           Kate

The result of a compare on these files would be:
DMSCMP179I Comparing EMPLOYEE LIST A with EMPLOYEE LIST B
Kathy
Tom
Diana
Kathy
Kate
Diana
DMSCMP010E Premature EOF on file EMPLOYEE LIST A
Ready(00004); T=0.01/0.01 08:14:09
The COMPARE command did not recognize the that files were identical except for one line. It simply compared each line on a line-by-line or record-for-record basis and displayed each dissimilar record. It did, however, indicate that one file contained more records than the other.

For more information on the COMPARE command, see z/VM: CMS Commands and Utilities Reference.