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xindy is a flexible program for sorting and formatting book indexes. It was written by Joachim Schrod as a successor to MakeIndex. xindy supports indexing for a variety of programs, including especially LaTeX and troff, and produces complex indices of the data.
xindy is cited as one of the most widely used indexing programs for LaTeX.[1] Unlike MakeIndex, xindy features strong support for many languages in addition to English, and many standard character encodings including Unicode.[2]
xindy is licensed under the GNU GPL.[3]