The plakar stdio command runs a plakar server listening on its standard input.
Its purpose is to ease the tunneling of plakar in different protocols:
if plakar stdio can be ran on the other end of a connection,
then it can consume the raw data from a socket and the client side can send plakar packets.
This is currently used for SSH support,
where the client has the other end execute plakar stdio and use the SSH connection as a tunnel.
There’s no point in running that command directly.
plakar stdio
$ plakar stdio