$ sh.pl
<initialization successful>
Can't call method "readline" on an undefined value at Term/Shell.pm line 104.

$ perl5.26.1 -d ./sh.pl

Loading DB routines from perl5db.pl version 1.51
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

19:     my %options = ();
20:     GetOptions(\%options,
24:     usage(0) if $options{help};
26:     my $shell = SH::Shell->new;
  DB<1>
<initialization successful>
28:     $shell->cmdloop;
  DB<1> n
shell> q


# sh.pl
<initialization successful>
shell> q