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From: daveb@rtech.UUCP
Newsgroups: comp.unix.questions
Subject: RE: why does this script... ( : and # )
Message-ID: <913@rtech.UUCP>
Date: Mon, 15-Jun-87 01:45:58 EDT
Article-I.D.: rtech.913
Posted: Mon Jun 15 01:45:58 1987
Date-Received: Tue, 16-Jun-87 01:27:41 EDT
Reply-To: daveb@rtech.UUCP (Dave Brower)
Organization: Relational Technology, Alameda CA
Lines: 35

As Doug Gwyn noted, the Bourne shell ':' is a command, not a comment
character.  However, it is still what I suggest you put in the head of
your  shell scripts for maximum portability.

It's clear you can't have a '#', because that implies csh on some kernels.
You can't rely on '#!/bin/sh', because some kernels don't undertand it.
(Yes, there are some that recoginize '#', but not '#!/...").

One option is to put a blank line at the beginning, which will result in
Bourne shell execution.  Unfortunately, blank lines have an annoying
habit of being removed when someone casually edits a file.
			----------------
easy to lose this line->
			# submit -- run cmd in background, it's output to OUT
			nohup $* > OUT 2>&1 &

If you put a ':' on the first line, WITH NOTHING ELSE, you won't
accidentally delete the line and you will get /bin/sh.  Why ':'?  Because
it's easy to type, innocuous, and usually a built-in making it cheap to
use.
			----------------
harder to lose this---->:
			# submit -- run cmd in background, it's output to OUT
			nohup $* > OUT 2>&1 &

You are asking for trouble if you put comments on the line with the ':'

			----------------
NO NO NO--------------->: submit -- run cmd in background, it's output to OUT
			nohup $* > OUT 2>&1 &


-dB
-- 
{amdahl, cbosgd, mtxinu, ptsfa, sun}!rtech!daveb daveb@rtech.uucp