open(OUTPUT, " > eol_dos.out") or die $!;
print OUTPUT <<EOL;
dir
EOL

##</code><code>##

>ver

Microsoft Windows XP [Version 5.1.2600]

>perl a.pl && type eol_dos.out
dir

##</code><code>##

open(OUTPUT, " > eol_dos.out") or die $!;
print OUTPUT <<EOL;
ls -1
EOL

##</code><code>##

$ uname
Linux

$ perl a.pl && cat eol_dos.out
ls -1

##</code><code>##

sqlplus -S "/as sysdba" <<"SQLEND"
set heading off
alter session set nls_date_format = 'DD-MON-YYYY HH24:MI:SS'
;

select 'Connected to the database on ' || sysdate
from dual
;
SQLEND

##</code><code>##

my @cmd = (
    sqlplus => (
        '-S',
        '/as' => 'sysdba',
    )
);

open(my $to_sqlplus, '|-', @cmd)
    or die("Can't launch sqlplus: $!\n");

print $to_sqlplus <<'__EOI__';
...
__EOI__

close($to_sqlplus);

##</code><code>##

use IPC::Open2 qw( open2 );

my @cmd = (
    sqlplus => (
        '-S',
        '/as' => 'sysdba',
    )
);

local *TO_SQLPLUS;
my $pid = open2('>&STDOUT', *TO_SQLPLUS, @cmd)
    or die("Can't launch sqlplus: $!\n");

print TO_SQLPLUS <<'__EOI__';
...
foo
bar
...
__EOI__

close(TO_SQLPLUS);
waitpid($pid,0);