The GenPak (GP) package contains many command-line utilities which fullfill a whole bunch of tasks, from DNA sequence searches to restriction analysis and determining the melting temperature of oligonucleotides. GP utilities can convert DNA / RNA to protein, determine codon usage / GC contents, do promotor searches, calculate Tm, search for restriction sites, convert sequences into numerical representations and much more. You most likely want to install Arka, which provides a GUI for GenPak.