This is GNU gperf. It is a program that generates perfect hash functions for sets of key words. A perfect hash function is: A hash function and a data structure that allows recognition of a key word in a set of words using exactly 1 probe into the data structure. The doc/gperf.html file explains how the program works, the form of the input, what options are available, and hints on choosing the best options for particular key words set. See the file NEWS for a list of major changes in the current release. See the file INSTALL for compilation and installation instructions. Output from the GPERF program is used to recognize reserved words in the GNU C, GNU C++, and GNU Pascal compilers, as well as with the GNU indent program. For general documentation on the coding and usage standards this distribution follows, see the GNU standards document ftp://ftp.gnu.org/pub/gnu/standards.*, especially the 'Makefile Conventions', 'Configuration', and 'User Interfaces' sections. Mail suggestions and bug reports to <firstname.lastname@example.org>. When reporting bugs, please include in the subject line the package name and version (output of 'gperf --version') for which you found a problem.