fontcode is a collection of C libraries and utility programs for manipulating TrueType fonts, developed for use in the Prince formatter and made available under an open-source license.
Currently it includes the following programs:
subset, which can be applied to TrueType fonts to
produce a new font that contains a subset of the glyphs found in the
original font, handy for saving space on disk and in PDF files.
font_info, which can be applied to font files to print
information about the font, including the available features and ligatures
found in the OpenType glyph substitution table (GSUB).
To build these programs you will require the FreeType library.
To checkout the code from the Subversion repository:
svn co https://fontcode.svn.sourceforge.net/svnroot/fontcode/trunk fontcode
For more information, see the SourceForge project page for fontcode.