/FILE (default)

    Calculates a file checksum.

    By default, the XOR algorithm (/ALGORITHM=XOR) is used for the
    checksum. The /FILE qualifier also implies a default file type
    of .DAT. By default, unsigned decimal checksum value is saved in
    the DCL symbol CHECKSUM$CHECKSUM and not output to the screen. By
    specifying /SHOW=DATA, the full filename of the specified input
    file is output in addition to the file checksum, an unsigned
    decimal value.

    The /ALPHA, /I64, or /VAX platform qualifiers do not influence
    the file checksum result. However, /ALPHA and /VAX prohibit the
    /SHOW qualifier because these qualifiers were not available on
    the original Checksum utility for Alpha systems.