$ cat -vET ttt
#!/usr/bin/perl -apF$
split;$

$ perl -le 'print $]'
5.008

$ perl -MO=Deparse ttt
LINE: while (defined($_ = <ARGV>)) {
    our(@F) = split(" ", $_, 0);
    split(" ", $_, 0);
}
continue {
    print $_;
}
ttt syntax OK
$