I have run into the same thing trying to gather up a couple hundred lines. I ended up getting it to work using print and waitfor. Using your example it would look like this: 
$t->print("ps -elf");
@ps = $t->waitfor('/your_stuff/');

[download]
with 'your_stuff' being what you are looking for in the command. I found this in the the Network Programming with Perl book by Lincoln Stein. A quite handy book by the way. Hope this helps.

In reply to Re: maximum result size for Net::Telnet's cmd() method by odha57
in thread maximum result size for Net::Telnet's cmd() method by dsb

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