Re: distinguishing shells

[<dws@ssec.wisc.edu>]

# How about
# 	@ {} || echo this is sh

Unfortunately that generates an error message from sh since it cannot
find a command named '@'.  The only thing I can think of that runs in
both without syntax errors is something like

	test "" '=' '' && {
		echo NOT rc or es
	} || {
		echo rc or es
	}

but that does require using 'test'.

If you've already defined an rc or es function named ':' which returns
false, then it's easy:

	: && {
		echo NOT rc or es
	} || {
		echo rc or es
	}

But I think this is worse than using 'test'.

sh-like syntax and rc-like syntax are so different that I doubt there
is enough in common to allow distinguising between the two without
resorting to an external command.  I would love to be proven wrong
about this.

DaviD W. Sanderson                                    dws@ssec.wisc.edu
Space Science and Engineering Center    University of Wisconsin-Madison
"The Noah Webster of smileys"    - The Wall Street Journal, 15 Sep 1992