Genpak is a small set of utilities designated to process DNA, RNA, and protein sequences in a very Un*x-like manner. This way, Genpak programs can be combined using pipes and redirections, as well as easily incorporated into CGI scripts. The utilities include a program for calculating GC content, Tm, translating DNA/RNA sequences into protein sequences, quick sequence retrieval, random sequence generation, and finding promoter sequences using a Hertz matrix.