echo print join ' ', $0, $R > switch-test.pl

# after the program name
perl -s switch-test.pl  -R=OK
switch-test.pl OK

# before an argument of --
perl -s switch-test.pl  -R=OK --
switch-test.pl OK

# wrong usage
perl -s switch-test.pl -- -R=OK
switch-test.pl

##</code><code>##

# after the program name
perl -s -e "print join ' ', $0, $R"  -R=OK
Unrecognized switch: -R=OK  (-h will show valid options).

# before an argument of --
perl -s -e "print join ' ', $0, $R"  -R=OK --
Unrecognized switch: -R=OK  (-h will show valid options).

# it works in the opposite way of what perlrun states
perl -s -e "print join ' ', $0, $R" -- -R=OK
-e OK

##</code><code>##

perl -snwe "print join ' ', $0, $R, $/" -- -R=OK lorem.txt

-e OK
-e OK
-e OK
-e OK

##</code><code>##

perl -wse  "print join ' ', $0, $R" -- -R=OK
-e OK

perl -swe  "print join ' ', $0, $R" -- -R=OK
-e OK

perl -sew  "print join ' ', $0, $R" -- -R=OK

#what the hell?! ..no output :)