MakeIndex is a general purpose index processor. It takes one or more raw index files (normally generated by a formatter), sorts the entries, and produces the actual index file. It is not dependent on any particular format of raw index file, although the .IDX file generated by LaTeX is the default. Up to three levels (0, 1, and 2) of subitem nesting within the same entry is supported. The input format may be redefined in a style file so that raw index or glossary output from other formatters may be processed. The style file also defines the style of output index file. Unless specified otherwise, the file name base of the first input file (idx0) is used to determine other related input/output files. The default input file type is .IDX.
MAKEINDEX [options] idx0 [idx1 idx2 ...]