SPUG:-s option doesn't always work!

[Tim Maher]

SPUGsters,

I don't use the -s invocation option very often, but for certain
categories of students, I think it works well.  So imagine my surprise
when I learned today that -s on the shebang line seems to be ignored
when the script is invoked as an argument to the perl command!
None of the other invocation options I can think of works like that,
except -T, and there are good reasons for that -- but not for this,
AFAIK.

I don't find any warning about this goofy behavior in the documentation.

Can anybody shed some light on this?

-Tim

NOTE on session transcript: The edited output appears in the
original file, where you can't see it.

$ ./change_file5 -old=e -new=E motd
Arguments are: motd
(That's what I want)

$ perl ./change_file5 -old=E -new=e motd
Arguments are: -old=E -new=e motd
(That's undesirable!)

Usage: ./change_file5 -old='old' -new='new' f1 [f2...]
BEGIN failed--compilation aborted at ./change_file5 line 13.

$ perl -s ./change_file5 -old=e -new=E motd
Arguments are: motd
(That's what I want, but not how I want to get it)

$ perl -v
This is perl, v5.8.0 built for i586-linux-thread-multi

$ cat change_file5
#! /usr/bin/perl -wlps -i.bak

BEGIN {	
	$USE="Usage: $0 -old='old' -new='new' f1 [f2...]";

	warn "Arguments are: @ARGV\n"; # to debug -s handling problem

	# Really need more stringent test, but students not ready yet
	defined $old and defined $new or die "$USE\n";	# must have strings
	@ARGV > 0 or die "$USE\n";	# mut have at least one filename
} 
s/$old/$new/g;

----- End forwarded message -----

-- 

-Tim
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