PS_View is a PostScript and PDF previewer. It is multiplatform (Windows, Linux and Mac OS X), GUI program based on the Ghostscript engine. Key features include huge magnification, fast viewing of large documents, exact measuring, and restart.
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.