RTK is a program devoloped in C to generate reports from a variety of sources (text files, SQL Servers, XML,... ) and to a variety of destinations (text files, graphical view, HTML, PostScript, etc).
gv allows a user to view and navigate through PostScript and PDF documents on an X display by providing a user interface for the ghostscript interpreter. It is based on an older viewer called Ghostview by Tim Thiesen.