FWIW, as of 2023, Preview no longer supports postscript files. Which is pretty annoying if you like to hand write postscript.
From that Apple note, a nice to know is that you can directly drag a ".ps" file on to the printer queue and it will be printed (assuming your printer talks postscript!):
If your printer supports PostScript, you can continue to print .ps and .eps files by dragging them into your printer queue: select your printer in Printers & Scanners settings, click the Printer Queue button, then drag the file into the printer queue window to print it.
I've justTo let me view a .ps in macOS I’ve installed the ghostscript suite, which includes tools to convert ps.ps files to pdf files. There're options for installing at Installing Ghostscript on Mac OS X.
I took the brew option: brew install ghostscript
.
There's no "ghostscript" app or command installed, but you get a whole bunch of tools, and one is ps2pdf
that will take your ".ps" file as an argument and write a similarly named ".pdf".