LDATTACH(8)		     System Administration		   LDATTACH(8)

NAME
       ldattach - attach a line discipline to a serial line

SYNOPSIS
       ldattach [-1278denoVh] [-i iflag] [-s speed] ldisc device

DESCRIPTION
       The ldattach daemon opens the specified device file (which should refer
       to a serial device) and attaches the line discipline ldisc to it for
       processing of the sent and/or received data. It then goes into the
       background keeping the device open so that the line discipline stays
       loaded.

       The line discipline ldisc may be specified either by name or by number.

       In order to detach the line discipline, kill(1) the ldattach process.

       With no arguments, ldattach prints usage information.

LINE DISCIPLINES
       Depending on the kernel release, the following line disciplines are
       supported:

       TTY(0)
	   The default line discipline, providing transparent operation (raw
	   mode) as well as the habitual terminal line editing capabilities
	   (cooked mode).

       SLIP(1)
	   Serial Line IP (SLIP) protocol processor for transmitting TCP/IP
	   packets over serial lines.

       MOUSE(2)
	   Device driver for RS232 connected pointing devices (serial mice).

       PPP(3)
	   Point to Point Protocol (PPP) processor for transmitting network
	   packets over serial lines.

       STRIP(4); AX25(5); X25(6)
	   Line driver for transmitting X.25 packets over asynchronous serial
	   lines.

       6PACK(7); R3964(9)
	   Driver for Simatic R3964 module.

       IRDA(11)
	   Linux IrDa (infrared data transmission) driver - see
	   <http://irda.sourceforge.net/>

       HDLC(13)
	   Synchronous HDLC driver.

       SYNC_PPP(14)
	   Synchronous PPP driver.

       HCI(15)
	   Bluetooth HCI UART driver.

       GIGASET_M101(16)
	   Driver for Siemens Gigaset M101 serial DECT adapter.

       PPS(18)
	   Driver for serial line Pulse Per Second (PPS) source.

       GSM0710(21)
	   Driver for GSM 07.10 multiplexing protocol modem (CMUX).

OPTIONS
       -1, --onestopbit
	   Set the number of stop bits of the serial line to one.

       -2, --twostopbits
	   Set the number of stop bits of the serial line to two.

       -7, --sevenbits
	   Set the character size of the serial line to 7 bits.

       -8, --eightbits
	   Set the character size of the serial line to 8 bits.

       -d, --debug
	   Keep ldattach in the foreground so that it can be interrupted or
	   debugged, and to print verbose messages about its progress to
	   standard error output.

       -e, --evenparity
	   Set the parity of the serial line to even.

       -i, --iflag value...
	   Set the specified bits in the c_iflag word of the serial line. The
	   given value may be a number or a symbolic name. If value is
	   prefixed by a minus sign, the specified bits are cleared instead.
	   Several comma-separated values may be given in order to set and
	   clear multiple bits.

       -n, --noparity
	   Set the parity of the serial line to none.

       -o, --oddparity
	   Set the parity of the serial line to odd.

       -s, --speed value
	   Set the speed (the baud rate) of the serial line to the specified
	   value.

       -c, --intro-command string
	   Define an intro command that is sent through the serial line before
	   the invocation of ldattach. E.g. in conjunction with line
	   discipline GSM0710, the command 'AT+CMUX=0\r' is commonly suitable
	   to switch the modem into the CMUX mode.

       -p, --pause value
	   Sleep for value seconds before the invocation of ldattach. Default
	   is one second.

       -h, --help
	   Display help text and exit.

       -V, --version
	   Display version and exit.

AUTHORS
       Tilman Schmidt <tilman@imap.cc>

SEE ALSO
       inputattach(1), ttys(4)

REPORTING BUGS
       For bug reports, use the issue tracker
       <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY
       The ldattach command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.41.2		  2025-09-22			   LDATTACH(8)