open( SH, "| /path/to/bash" ) or die "Can't open a shell: $!";
my @scripts;
{
  local $/ = undef;
  for my $file ( "first_shell_script", "second_shell_script" ) {
      open( SCR, $file ) or die "couldn't read $file: $!";
      push @scripts, <SCR>;
      close SCR;
  }
}
print SH $scripts[0];
print SH $scripts[1];

# and then do whatever magical stuff this shell can do,
# now that it has these scripts in its arsenal...