The DOC format is native to Microsoft Office Word, but other software, such as the free softwaregui programs OpenOffice, AbiWord and KWord, can create and read .doc files. Command line programs in the Unix shell which can convert files from the DOC format to plain text or other standard formats include the wv library, which itself is used directly by AbiWord and as a source of ideas and some coding by KWord. Due to the closed nature of the .doc file format, high-level formatting (including headers and footers) is often lost when written in one program and opened in the other. (wikipedia.org)
