The DIFFERENCES command compares the contents of two files. If
    CMS finds differences, it creates a file named first-file-name.DIF
    in your current default directory (unless /OUTPUT is in effect.)
    If the files are the same, it issues a message to that effect
    and does not create a differences file. By default, CMS compares
    two files that are not located in a CMS library. However, you can
    direct CMS to use element generations from the current library by
    specifying the /GENERATION qualifier on one or both of the file
    name parameters.

    Note: If both file1 and file2 are element generations, both
    generations must reside in the same library of the search list
    or an error will occur.

    A difference is defined as one of the following:

    o  A line or lines that are in one file and not in the other.

    o  A replacement of n lines by m lines (n may or may not be equal
       to m).

    Only the lines that differ are displayed in the differences file
    (unless you specify /FULL).

    A heading at the beginning of the differences file includes the
    name of the user that issued the command, the date and time the
    command was issued, and the file specifications of the two files
    being compared. If you direct CMS to use element generations and
    you have specified the /FORMAT option generation-differences,
    the differences listing contains a section labeled "Generation
    Differences" that contains the replacement history for the
    element. Each generation used in the comparison is identified by
    an asterisk (*) in the first column of the transaction record.
    The differences between the files are contained in a section
    labeled "Text Differences." By default, each difference is
    formatted with the line or lines from the first file followed by
    the differing line or lines from the second file. If a difference
    consists of a line or lines in one file but not the other,
    only the lines from the file containing the additional text are
    displayed.

    If you specify the /SKIP, /SENTINEL, and /IGNORE qualifiers on the
    same command line, they are processed in the following order:

    (1) /IGNORE=HISTORY
    (2) /IGNORE=NOTES
    (3) /SKIP
    (4) /SENTINEL
    (5) /IGNORE options other than HISTORY or NOTES

    For example, if you specify /SKIP=5 and /SENTINEL=("sushi","bar"),
    DIFFERENCES disregards the first 5 lines in each of the compared
    files, and then searches the remainder of each file for the
    sentinel character strings "sushi" and "bar".