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nullmodem - Man Page

a Utility to loopback Pseudo-Terminals


nullmodem [-F] [-V] [-q] [-r] [-m] tty...


nullmodem creates a virtual network of Pseudo-Terminals. It can be used as an adapter to connect two programs that normally need serial interface cards.


-F,  --foreground

Unlike normal operation, nullmodem will not detach from the terminal when given this option. Some debugging informations will be visible.

-q,  --quiet

Start quietly - for init scripts.

-v,  --verbose

Print debug info.

-V,  --version

Print the version number and exit.

-r,  --realtime

Start with realtime priority (i.e. use the round-robin scheduler). This requires nullmodem to run with root privileges.

-m,  --memorylock

Lock the executable of nullmodem to RAM. This keeps nullmodem from being swapped out.

--setuid n

Set the UserID (UID) of the pseudo terminal spacial files to n.

--setgid n

Set the GroupID (GID) of the pseudo terminal spacial files to n.


Use blocking IO to handle the interfaces (default: NONBLOCKing).


Juergen Rinas <jrinas@gmx.de>

See Also

kissnetd(8), openpty(3)


JULY 2004 Linux User Manuals