Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!usc!apple!snorkelwacker.mit.edu!bloom-beacon!eru!kth.se!sunic!mcsun!ukc!keele!nott-cs!piaggio!anw From: anw@maths.nott.ac.uk (Dr A. N. Walker) Newsgroups: comp.lang.postscript Subject: Re: How can I tell if a file is "postscript" Message-ID: <1991Mar21.192020.6338@maths.nott.ac.uk> Date: 21 Mar 91 19:20:20 GMT References: <1991Mar13.160331.25024@maths.nott.ac.uk> <13109@wraxall.inmos.co.uk> <1991Mar19.052103.9026@ferret.ocunix.on.ca> Reply-To: anw@maths.nott.ac.uk (Dr A. N. Walker) Organization: Maths Dept., Nott'm Univ., UK. Lines: 78 In article <1991Mar19.052103.9026@ferret.ocunix.on.ca> clewis@ferret.ocunix.on.ca (Chris Lewis) writes: [I wrote] >>> Just so. Now think how many things break if "lpr B" lists B >>> if the printer is a simple lineprinter but produces a fancy graphic >>> if we upgrade it to a LaserWriter. > >On the contrary, I'd suggest that it was no longer broken. Bleeah! If you've been listing a project to the lineprinter, as it develops, for weeks, months, years; and you come in one morning to find a shiny new printer in place; and you type "lpr myfile" just as you always used to; and you get an abstract greyish bitmap instead of your listing; where then is the break? >A truly smart spooler would figure out what printers are appropriate >for a given magic cookie, and route the results there. Otherwise, >you're expecting everybody to remember which printers can handle a given >format and/or remember lots of obscure options to tell the printer to >go into the correct mode. But this is backwards from the original problem. Should a file with *no* cookie be cooked automagically? For which printer? Should I have to remember lots of cookies, so that when I have a file which, by chance, starts with a magic cookie for some remote printer, I remember to encapsulate it by hand to that it gets listed locally instead of graphiced [:-)] remotely? Why does anything need to be so smart? *My* files don't usually have the magic cookies -- the cookies are put in by the programs that create the formats, and those programs can equally well direct the results to the appropriate printer [at least as an option]. The spooler should look after just one activity -- shovelling files, correctly sequenced and separated, out to printers [etc]. Serious smarts should be handled by conversion programs (equivalently, by virtual printers). > But I would contend that someone generating postscript >usually doesn't want to see the postscript listing, they want to see >the "graphic" that the postscript listing represents. In those rare >occasions where the user wants to see the internal language, [...] PostScript gets generated two ways -- by program, and by hand. When it is generated by program, you're right. But when I write PS, certainly I want to test it, but I also want to get file listings. >Run the bare postscript thru "pr" - not only do you get the output >nicely paginated with page numbers, the "%!" doesn't even get recognized >because it's no longer first in the file. So: you say "lpr file" to get graphics or some listings, and "pr file | lpr" to get other listings. I say "lpr file" to get graphics, and "list file" to get listings [or I would, except that the actual commands are more mnemonic for our actual devices]. I know which I prefer! >>If you object to files starting with %! being treated different from >>others that don't, what is your view on executable files that start >>with #! /bin/sh ????? I don't much care for it. But I can live with it, recognising it as an efficiency hack for the kernel; note that the actual behaviour (eg on SunOS) is the opposite way round from your spooler. If I try to run a shell script that doesn't begin "#! /bin/sh", it fails, rather than calling up some mythical ensheller. >More to the point, what about when "file" says: > > executable (RISC System/6000 V3.1) or object module not stripped > >Blindly routing it to a printer is stupid. Better than blindly turning it into PostScript! -- Andy Walker, Maths Dept., Nott'm Univ., UK. anw@maths.nott.ac.uk