✏ 编辑: 5.A.top

#!/usr/bin/perl
#	Here we are doing this again only this time we'll do it
#without Echoing the password.

$RSH='/usr/bin/ssh';

$host_to_login_to=shift(@ARGV);

use Expect;

print "Enter password: ";
# First we have to initialize STDIN in to an expect object.
$stdin=Expect->exp_init(\*STDIN);
# Now turn off echoing
$stdin->exp_stty('-echo');
# The easy way to do this is:
#$password=<STDIN>;
#chop $password;
# The somewhat harder way is to use $stdin->expect. This would look like:
#
 ($match_num,$error,$match,$before,$after)=$stdin->expect(undef,"\r");
 $password = $before;
# Turn echo back on
$stdin->exp_stty('echo');
# print that newline that wasn't echoed
print "\n";

$rsh=Expect->spawn($RSH,$host_to_login_to);

# Look for a password prompt.
$rsh->expect(30,'-re','word:\s$')||(die"Never got password prompt\n");

print $rsh "$password\r";

# Look for a prompt. Prompt can be # $ > or ] followed by a whitespace.
$prompt  = '[\]\$\>\#]\s$';

# Note the use of -re
$rsh->expect(30,'-re',$prompt)||(die "Never got prompt on host\n");

# Start top
print $rsh "exec top\r";

# OK, now return control to user.
$rsh->interact();

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