perl expect

janasec has asked for the wisdom of the Perl Monks concerning the following question:

Hi I am having difficulty in understanding expect module

#!/usr/bin/perl
use Expect;
$Expect::Exp_Internal = 1;

my $host = "10.227.2.20";
my $username = "root"; 
my $pass = "Pass1234";
my $expect = Expect->new;

my $expect = Expect->spawn("ssh $host -l $user") or die;
$expext->send("$pass");
$cmd = `ls`;
$expect->send("$cmd");
print "$expect\n";
[download]

in the above code iam not seeing anything and I need list the files,perform some remote processing on the system and read the out put

basically i want to run commands on the linux machine like 'ls','ifconfig','ping' and return their output back from the remote system

Comment on perl expect Download Code

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Re: perl expect by Corion (Patriarch) on Nov 26, 2015 at 13:58 UTC
$cmd = `ls`; [download] What is this line supposed to do? Have you printed `$cmd` to verify your assumption? Maybe you wanted to use single quotes instead? `$cmd = 'ls';` [download] See also Quote and Quote-like operators.	[reply] [d/l] [select]
Re: perl expect by salva (Canon) on Nov 26, 2015 at 15:20 UTC
Expect is not the best tool for doing that. Better use Net::OpenSSH or Net::SSH2.	[reply]
Re: perl expect by janasec (Sexton) on Nov 26, 2015 at 18:00 UTC
found some sample code i think for now this will do my $exp = Expect->spawn("telnet localhost") or die "Cannot spawn telnet: $!\n";; my $spawn_ok; $exp->expect($timeout, [ qr'login: $', sub { $spawn_ok = 1; my $fh = shift; $fh->send("$username\n"); exp_continue; } ], [ 'Password: $', sub { my $fh = shift; print $fh "$password\n"; exp_continue; } ], [ eof => sub { if ($spawn_ok) { die "ERROR: premature EOF in login.\n"; } else { die "ERROR: could not spawn telnet.\n"; } } ], [ timeout => sub { die "No login.\n"; } ], '-re', qr'[#>:] $', #' wait for shell prompt, then exit + expect ); [download] this is from the expect module from cpan Thanks all who tried	[reply] [d/l]
Re^2: perl expect by Anonymous Monk on Dec 07, 2016 at 19:51 UTC
Just a raw beginner's question but in the last line of this code - what does the 'gr' in `gr'[#>:] $'` mean? I realize he's looking for the prompt at the end of a line but I can't find a reference to the 'gr' syntax anywhere.	[reply] [d/l]
Re^3: perl expect by Anonymous Monk on Dec 07, 2016 at 19:57 UTC
See `qr/STRING/msixpodualn` in Regexp Quote Like Operators: This operator quotes (and possibly compiles) its STRING as a regular expression. ...	[reply] [d/l]
Re^4: perl expect by ogg (Initiate) on Dec 07, 2016 at 20:19 UTC
Re: perl expect by u65 (Chaplain) on Nov 26, 2015 at 23:24 UTC
Hi, janasec, this node explains the way I do similar things (in response to this node). A lot depends on how varied or unpredictable your work flow is.	[reply]