Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!tank!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.questions
Subject: Re: VMS: logicals  UNIX: links, but...
Summary: solving the wrong problem
Keywords: vms logical link
Message-ID: <16798@mimsy.UUCP>
Date: 8 Apr 89 05:50:11 GMT
References: <475@caldwr.UUCP>
Distribution: usa
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 35

In article <475@caldwr.UUCP> rfinch@caldwr.UUCP (Ralph Finch) writes:
>We run models, and often want to run the same model, simultaneously,
>in the same directory, with two different input files, and produce two
>corresponding output files.

Instead of using `logicals' or links or symlinks or . . ., just:

	model < input1 > output1 &
	model < input2 > output2 &

If the program uses several input files and creates several output
files, and if it cannot be made to name its files based on a single
argument, either of these more complex (and therefore less desirable)
approaches will work:

subdirectories:
	mkdir subdir1
	mkdir subdir2
		[ put specific inputs into subdirectories ]
	...
		[ put common inputs into both subdirectories ]
	ln common_files subdir1
	ln common_files subdir2
	(cd subdir1; ../model in1 out1 in2 out2) &
	(cd subdir2; ../model in1 out1 in2 out2) &

or (csh syntax) environment variables:
	(setenv INPUT1 inA1; setenv INPUT2 inA2; model &)
	(setenv INPUT1 inB1; setenv INPUT2 inB2; model &)

If you MUST emulate VMS logical symbols, use environment variables.
They are not identical, but they are usually close enough.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris