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From: dce@quacky.UUCP (David Elliott)
Newsgroups: comp.unix.questions
Subject: Re: ":" as a csh command
Message-ID: <121@quacky.UUCP>
Date: Sat, 20-Dec-86 12:57:18 EST
Article-I.D.: quacky.121
Posted: Sat Dec 20 12:57:18 1986
Date-Received: Sat, 20-Dec-86 22:39:00 EST
References: <666@cullvax.UUCP>
Reply-To: dce@quacky.UUCP (David Elliott)
Organization: MIPS Computer Systems, Sunnyvale, CA
Lines: 26

In article <666@cullvax.UUCP> drw@cullvax.UUCP (Dale Worley) writes:
>What does the ':' command to csh do?  When I type
>	:
>or
>	::
>or
>	::::::
>csh doesn't seem to do anything, but if I type
>	: a
>it says ":: Too many arguments".
>

It helps you prevent running a shell script with csh. A file beginning
with

	: run this with sh, not csh

will fail immediately if run by csh.

You see, you can no longer reliably distinguish csh and sh scripts
by looking for '#' as the first character, since AT&T Unix systems
allow # as a comment and do not have csh scripts (it sure would
be nice if everyone spoke #!).

			David Elliott
			Mips Computer Systems