[Thamesvalley-pm] using ssh within perl scripts

[Greg Matthews]

Stephen Cardie wrote:
> You can do this with IPC::Run.  A trivial example is shown below.  The 
> @hosts data structure contains a list of hosts to interrogate; each 
> element of this is a reference to a hash, the keys of which are 
> hostname, username and cmds.  The last is an array of filename and 
> command pairs, the command will be executed on the remote host and the 
> output recorded in the file. Obviously, this could be the same for every 
> host, in which case you'd remove if from the hash ref and just re-use 
> the array for each host (i.e. call it @cmds and remove the line 
> 'my(@cmds) = @{$host->{cmds}};' below.

this looks quite useful, I shall squirrel it away for future reference. 
Unfortunately, I can't guarantee the availability of IPC::Run. I shall 
have a close look at this module tho as it seems quite powerful.

thanks Stephen

GREG

> 
> This is quite Expect-like, and, as has been suggested, you could achieve 
> the same thing with Expect.pm, if you are more comfortable with that 
> environment.
> 
> ### BEGINS ####
> #!/usr/bin/perl
> use strict;
> use warnings;
> 
> use IO::File;
> use IPC::Run qw( start pump finish timeout );
> 
> my(@hosts) = (
>      { hostname => 'myhost.mydomain.com',
>        username => 'myusername',
>        cmds     => [
>            # Filename      Command
>          [ 'uname_a.txt', "uname -a\n"],
>          [ 'uname_s.txt', "uname -s\n"],
>        ],
>      },
> );
> 
> my($ssh_bin) = '/usr/bin/ssh';
> my($ssh_opts) = '-2';
> 
> for my $host (@hosts) {
>      my(@login) =
>          ($ssh_bin, $ssh_opts, join '@' => @{$host}{qw(username hostname)});
>      my(@cmds) = @{$host->{cmds}};
> 
>      my($h,$in,$out,$err);
>      $h = start( \@login, \$in, \$out, \$err, timeout( 3 ) );
> 
>      $in .= "\n";
> 
>      while (@cmds) {
>          my($file,$cmd) = @{(shift @cmds)};
>          $in .= $cmd;
> 
>          pump $h until ( $out=~/\n/ );
>          my($fh) = IO::File->new($file, 'w');
>          defined( $fh ) or die "Can\'t write to $file:$!";
>          $fh->print( $out );
>          $fh->close;
>          $out = '';
>      }
> 
>      $h->finish;
> }
> 
> exit;
> #### ENDS #####
> 
> 
> 
> 
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> Thamesvalley-pm at pm.org
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> 


-- 
Greg Matthews           01491 692445
Head of UNIX/Linux, iTSS Wallingford

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