sub ps_line {
    my $ps = shift;
    print join ' ', "$ps:\t", @{ (grep { $_->[0] == $$ }
                                   map { [ split ] }
                                  `$ps | tail -n +2`)[0] };
    print "\n";
}

print "\$0 = $0\n";
ps_line( 'ps' );
ps_line( 'ps ww' );
{
    local( $0 ) = 'nyuck' x 3;
    print "\$0 = $0\n";
    ps_line( 'ps' );
    ps_line( 'ps ww' );
}
print "\$0 = $0\n";
ps_line( 'ps' );
ps_line( 'ps ww' );
__END__
$0 = ./perlmonks.pl
ps:      875 pts/1 00:00:00 perl
ps ww:   875 pts/1 S+ 0:00 perl ./perlmonks.pl
$0 = nyucknyucknyuck
ps:      875 pts/1 00:00:00 perl
ps ww:   875 pts/1 S+ 0:00 nyucknyucknyuck
$0 = ./perlmonks.pl
ps:      875 pts/1 00:00:00 perl
ps ww:   875 pts/1 S+ 0:00 ./perlmonks.pl