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From: jms@cs.vu.nl (Jan-Mark)
Newsgroups: comp.os.minix
Subject: Re: test/[ solved; new question: executable scripts?
Summary: To some kernels #! is a magic number.
Message-ID: <9818@star.cs.vu.nl>
Date: 29 Apr 91 22:45:45 GMT
References: <1991Apr29.110459.25477@doe.utoronto.ca>
Sender: news@cs.vu.nl
Reply-To: jms@cs.vu.nl (Jan-Mark Wams)
Organization: VU Dept. of Computer Science, Amsterdam, The Netherlands
Lines: 39

In article <1991Apr29.110459.25477@doe.utoronto.ca>,
 	david@doe.utoronto.ca (David Megginson) writes:
#> 
#> Thank you to every one who sent me mail. The solution to using the
#> 
#> 	if [ <condition> ]
#> 
#> syntax in sh is to link test to [. test is even smart enough that it
#> looks for the ] if it is called as [.
#> 
#> I am also interested in executable scripts. Right now, when I make a
#> script executable, the kernel always seems to presume that it is for
#> sh. I would like to have executable scripts like
#> 
#> 	#!	/usr/gnu/bin/gawk
#> 
#> 	BEGIN { print "hello" }
#> 
#> 	/bug/ { print "Oh no!" }
#> 
#> 	END { print "bye" }
#> 
#> If this script were called "buggy", and I chmod'd it to make it
#> executable, I would expect it to run under gawk, but the kernel still
#> gives it to sh (can't find BEGIN...). Any advice, or is this another
#> incredible dumb question?

	To some kernels #! is a magicnumber. If a file has #! as first
	two bytes, the rest of the line is put into an array and used 
	in an ``system ()'' call. So hack the kernel is you want this!
	But are you sure you DO want this, remember; small is .....

	Jan-Mark.

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				 (:>	jms
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