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
In order to detach the line discipline, kill(1) the ldattach
With no arguments, ldattach prints usage information.
Depending on the kernel release, the following line disciplines
The default line discipline, providing transparent operation
(raw mode) as well as the habitual terminal line editing
capabilities (cooked mode).
Serial Line IP (SLIP) protocol processor for transmitting
TCP/IP packets over serial lines.
Device driver for RS232 connected pointing devices (serial
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
Driver for Simatic R3964 module.
Linux IrDa (infrared data transmission) driver - see
Synchronous HDLC driver.
Synchronous PPP driver.
Bluetooth HCI UART driver.
Driver for Siemens Gigaset M101 serial DECT adapter.
Driver for serial line Pulse Per Second (PPS) source.
Driver for GSM 07.10 multiplexing protocol modem (CMUX).
Set the number of stop bits of the serial line to one.
Set the number of stop bits of the serial line to two.
Set the character size of the serial line to 7 bits.
Set the character size of the serial line to 8 bits.
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.
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.
Set the parity of the serial line to none.
Set the parity of the serial line to odd.
-s, --speed value
Set the speed (the baud rate) of the serial line to the
-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.
Display version information and exit.
Display help text and exit.
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/>. This page
is part of the util-linux (a random collection of Linux
utilities) project. Information about the project can be found at
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have
a bug report for this manual page, send it to
firstname.lastname@example.org. This page was obtained from the
project's upstream Git repository
2021-08-27. (At that time, the date of the most recent commit
that was found in the repository was 2021-08-24.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in
this COLOPHON (which is not part of the original manual page),
send a mail to email@example.com
util-linux 2.37.85-637cc 2021-04-02 LDATTACH(8)