davem@mythtv:~$ which perl
/usr/bin/perl
davem@mythtv:~$ ll /usr/bin/perl
-rwxr-xr-x  1 root root 1057324 Nov  6  2004 /usr/bin/perl
davem@mythtv:~$ vi /tmp/foo.pl
davem@mythtv:~$ chmod +x /tmp/foo.pl
davem@mythtv:~$ cat /tmp/foo.pl
#!/usr/bin/perl
print "hello world\n";

davem@mythtv:~$ /tmp/foo.pl
hello world
davem@mythtv:~$

#!/usr/bin/perl

# This is only the necessary parts of the original script (found in the link
#bellow) necessary to change the channels in the box.
# dss_control: Remote control of a Sony DSS unit via the serial port
# By Josh Wilmes (http://www.hitchhiker.org/dss)
# Based on info from http://www.isd.net/mevenmo/audiovideo.html
#
# I take no responsibility for any damage this script might cause.
# Feel free to modify and redistribute this as you see fit, but please retain
# the comments above.

$|=1;
use POSIX qw(:termios_h);
use FileHandle;

$verbose=0;

%pkt_decode=("0xF0" => "START PKT",
"0xF1" => "ERR 1",
"0xF2" => "GOT EXTENDED",
"0xF4" => "END PKT",
"0xF5" => "ERR 2",
"0xFB" => "PROMPT");

%terminal=("0xF1" => -1,
"0xF4" => 1,
"0xF5" => -1);


%keymap=(right => "0x9a",
left => "0x9b",
up => "0x9c",
down => "0x9d",
favorite => "0x9e",
select => "0xc3",
exit => "0xc5",
9 => "0xc6",
8 => "0xc7",
7 => "0xc8",
6 => "0xc9",
5 => "0xca",
4 => "0xcb",
3 => "0xcc",
2 => "0xcd",
1 => "0xce",
0 => "0xcf",
ch_up => "0xd2",
ch_dn => "0xd3",
power => "0xd5",
jump => "0xd8",
guide => "0xe5",
menu => "0xf7");

my $serial=init_serial("/dev/ttyS0","9600");
#@ARGV = split //, join '', @ARGV;
$ret=&change_channel(@ARGV);

#foreach (@ARGV) {
#change_channel($_);
#}

exit(0);

sub change_channel {
my ($channel)=@_;

$_=sprintf("%4.4x",$channel);
($n1,$n2)=/(..)(..)/;

simple_command("0x46",$n1,$n2,"0x0");
}


sub simple_command {
if (defined(dss_command(@_))) {
return(1);
} else {
return(undef);
}
}

sub dss_command {
sendbytes("0xFA",@_);
return get_reply();
}

sub sendbytes {
(@send)=@_;
foreach (@send) { s/^0x//g; $_=hex($_); }
print "SEND: " if ($verbose);
foreach $num (@send) {
$str=pack('C',$num);
printf("0x%X [%s] ", $num, $str) if ($verbose);
syswrite($serial,$str,length($str));
}
print "\n" if ($verbose);
}

sub get_reply {
my $starttime=time();
my ($last,$ok,@ret);

print "RECV: " if ($verbose);

while (1) {
$ret=sysread($serial,$buf,1);
$str=sprintf("0x%2.2X", ord($buf));

# busy wait bad!
die ("Error ($str)\n") if (time() - $starttime > 8);
next if $str eq "0x00";

if ($pkt_decode{$str}) {
print $str if ($verbose);
print "[$pkt_decode{$str}] " if ($verbose);
} else {
$_=$str; s/^0x//g; $_=hex($_);
printf("$str(%3.3s) ",$_) if ($verbose);
push (@ret,$_);
}

$ok=1 if ($terminal{$str} > 0);
last if ($terminal{$str});
last if ($last eq "0xFB" && $str eq "0xFB");
$last=$str;
}
print "\n\n" if ($verbose);

return @ret if ($ok);
return undef;
}

sub init_serial {
my($port,$baud)=@_;
my($termios,$cflag,$lflag,$iflag,$oflag);
my($voice);

my $serial=new FileHandle("+>$port") || die "Could not open $port: $!\n";

$termios = POSIX::Termios->new();
$termios->getattr($serial->fileno()) || die "getattr: $!\n";
$cflag= 0 | CS8 | HUPCL | CREAD | CLOCAL;
$lflag= 0;
$iflag= 0 | IGNBRK | IGNPAR | IXON | IXOFF;
$oflag= 0;

$termios->setcflag($cflag);
$termios->setlflag($lflag);
$termios->setiflag($iflag);
$termios->setoflag($oflag);
$termios->setattr($serial->fileno(),TCSANOW) || die "setattr: $!\n";
eval qq[
\$termios->setospeed(POSIX::B$baud) || die "setospeed: \$!\n";
\$termios->setispeed(POSIX::B$baud) || die "setispeed: \$!\n";
];

die $@ if $@;

$termios->setattr($serial->fileno(),TCSANOW) || die "setattr: $!\n";

# This gets rid of all the special characters..
$termios->getattr($serial->fileno()) || die "getattr: $!\n";
for (0..NCCS) {
if ($_ == NCCS) { last; }

# Dont mess up XON/XOFF..
if ($_ == VSTART || $_ == VSTOP) { next; }

$termios->setcc($_,0);
}
$termios->setattr($serial->fileno(),TCSANOW) || die "setattr: $!\n";

return $serial;
}