Command line manipulation of BibTeX files: Pretty-printing data bases; Syntactic checks with error recovery; Semantic checks. Sorting and merging of data bases; Generation of uniform reference keys according to predefined rules or according to user specification; Selecting references used in one publication which are found by analyzing an aux file; Controlled rewriting of fields utilising regular expressions to specify the rewriting rules; Macro (String) expansion to eliminate the need of extra string definitions; Collecting statistics about one or more data bases. The author is Gerd Neugebauer.