Hello thanos1983!

Well, I decided to use a different approach instead of using $t->print and $t->waitfor, I decided to use line continuation character, and I discovered it worked very well! I found this code here and adapted for my needs, on which it fitted well. There says some shells have a limitation of 255 characters line limit.

sub cmd_unixlong {
        my ($obj, $cmd) = @_;
        my ($line, $pos);
        my $max_tty_line = 254;

        ## Start a Bourne shell.
        $obj->cmd(-string => "/usr/bin/env " .
                  "'PS1=<xPROMPTx> ' 'PS2=<xPROMPTx> ' /bin/sh -i",
                  -prompt => '/<xPROMPTx> $/')
            or return;

        ## Break-up the one large command line and send as shorter lin
+es.
        $pos = 0;
        while (1) {
            $line = substr $cmd, $pos, $max_tty_line;
            $pos += length $line;
            last unless $pos < length $cmd;

            ## Send the line with continuation char.
            $obj->cmd(-string => "$line\\",
                      -prompt => '/<xPROMPTx> $/')
                or return;
        }

        ## Send the last line and return the output.
        $obj->cmd("$line ; exit");

    } # end sub cmd_unixlong
[download]

I'm still using telnet, so I changed it to something more or less like this:

sub cmd_telnetlong {
        my ($obj, $cmd) = @_;
        my ($line, $pos);
        my $max_tty_line = 254;

        ## Break-up the one large command line and send as shorter lin
+es.
        $pos = 0;
        while (1) {
            $line = substr $cmd, $pos, $max_tty_line;
            $pos += length $line;
            last unless $pos < length $cmd;

            ## Send the line with continuation char.
            $obj->cmd(-string => "$line^",
                      -prompt => '/More?/i')
                or return;
        }

        ## Send the last line and return the output.
        return $obj->cmd("$line ; exit");
    } # end sub cmd_unixlong
[download]

As I haven't found anything to solve the line limitation, this workaround served me very well! Thanks all for your time!