[texworks] Batch Converting Postscript files to PDF files without leaving the windows open

[eSage Techie]

I have placed a similar request for help at tex.stackexchange.com/questions, so apologies if this reaches the same audience. I am hoping it won't.

With Mac OS 10.7.5 I need to convert about 13,800 PostScript files to PDF and find that of the apps that use Ghostscript and Apple's own distiller (Such as Preview or the PS-to-PDF app), only Ghostscript will work. I have tried the Ghostscript app Pstill, but it doesn't do a  good job in my case. 

I have installed TeXworks package and find that TeXworks and TeXShop correctly distill the PostScript files but leaves the PDFs on-screen, so batch processing means that the app takes progressively longer and longer to process files as the memory fills up and the screen is full of PDFs. Eg. The first 250 files take 5 minutes. The next 250 takes 10 minutes, and so on till the app stops responding. Even after completing only 250 files, TeXShop stops responding for ages so it tales a long time to start to close the on-screen PDFs.

To get around this problem, I figure that either TeXShop (1st preference as it seems faster) or TeXworks must be able to covert (distill) these files without leaving them open or without opening them on-screen in the first place.

So, question: How can TeXShop or any other similar GhostScript app be configured to batch process the files? I can't find built in tools for this but can't believe it's not possible. I considered using Automator app but gave up because i still couldn't find a way to progressively process the files and close the window after each conversion.

I am new to the whole PS to PDF distilling scene so I prefer a solution that's not very difficult to implement for a newbie. I am confident to mess with scripts and Terminal if I have clear instruction.

Any help is much appreciated.

----- configuration info -----
TeXworks version : 0.4.4r1004 (release)
Install location : /Applications/TeX/TeXworks.app
Library path     : /Users/esage/Library/TeXworks/
pdfTeX location  : not found
Operating system : Mac OS X 10.7.5 (Darwin Kernel Version 11.4.2: Thu Aug 23 16:26:45 PDT 2012; root:xnu-1699.32.7~1/RELEASE_I386)
Qt4 version      : 4.8.1 (build) / 4.8.1 (runtime)
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