World's Smallest Shell

 $| = 1;

 while (1) {
 print "perl% ";
 my $command = <STDIN>;
 last if $command eq '';
 chomp $command;
 my ($program, @args) = split /\s+/, $command;
 my $pid = fork;
 if (! defined $pid) { print STDERR "Couldn't fork: $!\n" }
 elsif ($pid != 0) { wait } # The parent
 else { exec $program, @args; # The child
 die "Couldn't exec: $!\n";
 }
 }