SKIP: {
	    skip("\$0 check only on Linux and FreeBSD", 2)
		unless $^O =~ /^(linux|freebsd)$/
		    && open CMDLINE, "/proc/$$/cmdline";

	    chomp(my $line = scalar <CMDLINE>);
	    my $me = (split /\0/, $line)[0];
	    is $me, $0, 'altering $0 is effective (testing with /proc/)';
	    close CMDLINE;
            # perlbug #22811
            my $mydollarzero = sub {
              my($arg) = shift;
              $0 = $arg if defined $arg;
	      # In FreeBSD the ps -o command= will cause
	      # an empty header line, grab only the last line.
              my $ps = (`ps -o command= -p $$`)[-1];
              return if $?;
              chomp $ps;
              printf "# 0[%s]ps[%s]\n", $0, $ps;
              $ps;
            };
            my $ps = $mydollarzero->("x");
            ok(!$ps  # we allow that something goes wrong with the ps command