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From: barrett@jhunix.HCF.JHU.EDU (Dan Barrett)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Script bits
Message-ID: <7564@jhunix.HCF.JHU.EDU>
Date: 13 Feb 91 19:34:00 GMT
References: <18ac1a05.ARN2ae4@prolix.pub.uu.oz.au>
Organization: The Johns Hopkins University - HCF
Lines: 33

In article <18ac1a05.ARN2ae4@prolix.pub.uu.oz.au> dac@prolix.pub.uu.oz.au writes:
>Having eight bits is kinda useful, Peter. The 'Script' bit is great. Whilst
>having the machine check to see if a file is a script, is plain dumb. There is
>no reason why a binary should start with any particular sequence of
>characters, right?

	Are you aware that all Amiga executable files start with the same
bytes?  That's how the Amiga can tell it is indeed a program, and not just
data.

>Therefore, there is no reason why some unlucky binary file could start with
>the text '.key', and then the script interpreter would be
>called instead of the program loader - which would try to 'execute' a binary.
>Not clever at all.

	UNIX does this.  The interpreter just fails on the file, as if it
had a syntax error.  Not a problem, really.
	Of course, the file would have to have its execute bit (incorrectly)
turned on in the first place.  A person might just as easily set the script
bit on a non-script file as set the execute bit on a non-executable.

	But you are right -- the method isn't perfect.  But neither is
having a different bit for each of 52 different interpreters (Shell,
AREXX, AmigaBasic, csh, sksh, etc etc), or the inability to run scripts
for "unsupported" interpreters.

                                                        Dan

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