use Net::FTP;

# this is wrong, because you cwd without checking
# if $ftp is really an object or it is undef
# (new() failed)
$ftp = Net::FTP->new("some.host.name", Debug => 0) ;
$ftp->cwd("/pub") ;

# This is right instead, and it comes straight from
# Net::FTP's documentation
# See how every method call is checked for success
$ftp = Net::FTP->new("some.host.name", Debug => 0)
  or die "Cannot connect to some.host.name: $@";
 
$ftp->login("anonymous",'-anonymous@')
  or die "Cannot login ", $ftp->message;
 
$ftp->cwd("/pub")
  or die "Cannot change working directory ", $ftp->message;
 
$ftp->get("that.file")
  or die "get failed ", $ftp->message;
 
$ftp->quit;