use strict;
use warnings;

# Env appears to be an ordinary hash
# 'TEMP' is present in the list of environment variables
# but 'temp' is not
printf "$_\n" foreach keys %ENV;

print "\n";

# this gives us the value of $ENV:TEMP
# which makes sense.
printf "uppercase 'temp' maps to %s\n",$ENV{TEMP};

# even though temp is not present in the
# list of keys,the same value appears as for
# $ENV{TEMP}
# This seems to make sense given the behavior of powershell
# (I am not quite sure what the relationship is between
# Windows environment variables and case,but this seems reasonable.)
printf "lowercase 'temp' maps to %s\n",$ENV{temp};

# However,%ENV is not a tied hash.
printf "Tie status: %s\n",tied(%ENV) // "not a tied variable";