open( E, ">", "check-env-$$.txt" ); # adjust path to suit your taste
print E "$_ => $ENV{$_}\n" for ( sort keys %ENV );
close E;

##</code><code>##

open( RED, "-|", "redmon arg1 ..." ) or die "redmon failed: $!";
while (<RED>) {
    # do stuff...
    print;
}