PICOCOM(1) User Commands PICOCOM(1)NAMEpicocom - minimal dumb-terminal emulation program
SYNOPSISpicocom [ options ] device
DESCRIPTION
As its name suggests, picocom(1) is a minimal dumb-terminal emulation
program. It is, in principle, very much like minicom(1), only it's
"pico" instead of "mini"! It was designed to serve as a simple, manual,
modem configuration, testing, and debugging tool. It has also served
(quite well) as a low-tech serial communications program to allow
access to all types of devices that provide serial consoles. It could
also prove useful in many other similar tasks.
When picocom starts it opens the terminal (serial device) given as its
non-option argument. Unless the --noinit option is given, it config‐
ures the device to the settings specified by the option-arguments (or
to some default settings), and sets it to "raw" mode. If --noinit is
given, the initialization and configuration is skipped; the device is
just opened. Following this, picocom sets the standard-input and stan‐
dard-output to raw mode. Having done so, it goes in a loop where it
listens for input from stdin, or from the serial port. Input from the
serial port is copied to the standard output while input from the stan‐
dard input is copied to the serial port. Picocom also scans its input
stream for a user-specified control character, called the escape char‐
acter (being by default C-a). If the escape character is seen, then
instead of sending it to the serial-device, the program enters "command
mode" and waits for the next character (which is called the "function
character"). Depending on the value of the function character, picocom
performs one of the operations described in the COMMANDS section below.
COMMANDS
Commands are given to picocom by first keying the espace character
which by default is C-a (see OPTIONS below for how to change it), and
then keying one of the function (command) characters shown here.
escape character
Send the escape character to the serial port and return to
"transparent" mode. This means that if the escape character
(C-a, by default) is typed twice, the program sends the escape
character to the serial port, and remains in transparent mode.
C-x Exit the program: if the --noreset option was not given then the
serial port is reset to its original settings before exiting; if
it was given the serial port is not reset.
C-q Quit the program without reseting the serial port, regardless of
the --noreset option.
C-p Pulse the DTR line. Lower it for 1 sec, and then raise it
again.
C-t Toggle the DTR line. If DTR is up, then lower it. If it is
down, then raise it.
C-backslash
Generate a break sequence on the serial line. A break sequence
is usually generated by marking (driving to logical one) the
serial Tx line for an amount of time coresponding to several
character durations.
C-b Set baurdate. Prompts you to enter a baudrate numerically (in
bps) and configures the serial port accordingly.
C-u Baud up. Increase the baud-rate. The list of baud-rates
stepped-through by this command is: 50, 75, 110, 134, 150, 200,
300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200.
If HIGH_BAUD support is compiled-in, then the following
baud-rates are also added to the list: 230400, 460800, 500000,
576000, 921600, 1000000, 1152000, 1500000, 2000000, 2500000,
3000000, 3500000, 4000000. Depending on you system, any of the
higher baud rates may be missing.
C-d Baud down. Decrease the baud-rate. The list of baud-rates
stepped-through by this command is the same as for the "baud-up"
command.
C-f Cycle through flow-control settings (RTS/CTS, XON/XOFF, none).
C-y Cycle through parity settings (even, odd, none).
C-i Cycle through databits-number settings (5, 6, 7, 8).
C-j Cycle through stopbits-number settings (1, 2).
C-c Toggle local-echo mode.
C-v Show program options (like baud rate, data bits, etc) as well as
the actual serial port settings. Only the options and port set‐
tings that can be modified online (through commands) are shown,
not those that can only be set at the command-line. See DISPLAY
OF OPTIONS AND PORT SETTINGS for details.
C-h or C-k
Show help or show keys. Prints a short description of all
available function (command) keys.
C-s Send (upload) a file. See SENDING AND RECEIVING FILES below.
C-r Receive (download) a file. See SENDING AND RECEIVING FILES
below.
After performing one of the above operations, the program leaves the
command mode and enters transparent mode. Example: To increase the
baud-rate by two steps, you have to type:
C-a, C-u, C-a, C-u
assuming of-course that C-a is the escape character.
OPTIONS
Picocom accepts the following command-line options.
--baud | -b
Defines the baud-rate to set the serial-port (terminal) to.
--flow | -f
Defines the flow-control mode to set the serial-port to. Must
be one of: x for xon/xoff (software) mode, h for hardware flow
control (RTS/CTS), n for no flow control. (Default: n)
--parity | -y
Defines the parity mode to set the serial-port to. Must be one
of: o for odd parity mode, e for even parity mode, n for no par‐
ity mode. (Default: n)
--databits | -d
Defines the number of data bits in every character. Must be one
of: 5, 6, 7, 8. (Default: 8)
--stopbits | -p
Defines the number of stop bits in every character. Must be one
of: 1, or 2. (Default: 1)
--escape | -e
Defines the character that will make picocom enter command-mode
(see description above). If x is given, then C-x will make pic‐
ocom enter command mode. (Default: a)
--echo | -c
Enable local echo. Every character being read from the terminal
(standard input) is echoed to the terminal (standard output)
subject to the echo-mapping configuration (see --emap option).
(Default: Disabled)
--noinit | -i
If given, picocom will not initialize, reset, or otherwise med‐
dle with the serial port at start-up. It will just open it.
This is useful, for example, for connecting picocom to
already-connected modems, or already configured ports without
terminating the connection, or altering the settings. If
required, serial port parameters can then be adjusted at
run-time by commands. (Default: Disabled)
--noreset | -r
If given, picocom will not reset the serial port when exiting.
It will just close the filedes and do nothing more. This is
useful, for example, for leaving modems connected when exiting
picocom. Regardless whether the --noreset option is given, the
user can exit picocom using the "Quit" command (instead of
"Exit"), which never resets the serial port. If --noreset is
given then "Quit" and "Exit" behave essentially the same.
(Default: Disabled)
--nolock | -l
If given, picocom will not attempt to lock the serial port
before opening it. Normally, depending on how it's compiled,
picocom attempts to get a UUCP-style lock-file (e.g.
'/var/lock/LCK..ttyS0') before opening the port, or attempts to
lock the port device-node using flock(2). Failing to do so,
results in the program exiting after emitting an error-message.
It is possible that your picocom binary is compiled without sup‐
port for locking. In this case the --nolock option is accepted,
but has no effect. (Default: Disabled)
--send-cmd | -s
Specifies the external program (and any arguments to it) that
will be used for transmitting files. If the argument to
--send-cmd is the empty string (''), the send-file command is
disabled. See SENDING AND RECEIVING FILES. (Default: sz -vv)
--receive-cmd | -v
Specifies the external program (and any arguments to it) that
will be used for receiving files. If the argument to
--receive-cmd is the empty string (''), the receive-file command
is disabled. See SENDING AND RECEIVING FILES. (Default: rz
-vv)
--imap Specifies the input character map (i.e. special characters to
be replaced when read from the serial port). See INPUT, OUTPUT,
AND ECHO MAPPING. (Defaul: Empty)
--omap Specifies the output character map (i.e. special characters to
be replaced before being written to serial port). See INPUT,
OUTPUT, AND ECHO MAPPING. (Defaul: Empty)
--emap Specifies the local-echo character map (i.e. special characters
to be replaced before being echoed-back to the terminal, if
local-echo is enabled). See INPUT, OUTPUT, AND ECHO MAPPING.
(Defaul: delbs,crcrlf)
--help | -h
Print a short help message describing the command-line options.
Picocom's version, ompile-time options, and enabled features are
also shown.
DISPLAY OF OPTIONS AND PORT SETTINGS
The "show program options" command (C-v), as well as the commands that
change program options (C-b, C-u, C-d, C-f, etc) print messages showing
the current values (or the new values, if they were changed) for the
respective options. If picocom determines that an actual serial-port
setting differs from the current value of the respective option (for
whatever reason), then the value of the option is shown followed by the
value of the actual serial-port setting in parenthesis. Example:
*** baud: 115200 (9600)
This means that a baud rate of 115200bps has been selected (from the
command line, or using commands that change the baudrate) but the
serial-port is actually operating at 9600bps (the driver may not sup‐
port the higher setting, and has silently replaced it with a safe
default, or the setting may have been changed from outside picocom).
If the option and the corresponding serial-port setting are the same,
only a single value is shown. Example:
*** baud: 9600
This behavioir was intriduced in picocom 2.0. Older releases displayed
only the option values, not the actual serial-port settings correspond‐
ing to them.
SENDING AND RECEIVING FILES
Picocom can send and receive files over the serial port using external
programs that implement the respective protocols. In Linux typical
programs for this purpose are:
· rx(1) - receive using the X-MODEM protocol
· rb(1) - receive using the Y-MODEM protocol
· rz(1) - receive using the Z-MODEM protocol
· sx(1) - send using the X-MODEM protocol
· sb(1) - send using the Y-MODEM protocol
· sz(1) - send using the Z-MODEM protocol
· ascii-xfr(1) - receive or transmit ASCII files
The name of, and the command-line options to, the program to be used
for transmitting files are given by the --send-cmd option. Similarly
the program to receive files, and its argumets, are given by the
--receive-cmd option. For example, in order to start a picocom session
that uses sz(1) to transmit files, and rz(1) to receive files, you have
to say something like this:
picocom--send-cmd "sz -vv" --receive-cmd "rz -vv" ...
If the argument to the -send-cmd option, or the argument to the
--receive-cmd option is the empty string, then the respective command
is disabled. For example, in order to disable both the "send" and the
"receive" commands you can invoke picocom like this:
picocom--send-cmd '' --receive-cmd '' ...
A picocom session with both, the send- and the receive-file commands
disabled does not fork(2) and does not run any external programs.
During the picocom session, if you key the "send" or "receive" commands
(e.g. by pressing C-a, C-s, or C-a, C-r) you will be prompted for a
filename. At this prompt you can enter one or more file-names, and any
additional arguments to the transmission or reception program. Com‐
mand-line editing and rudimentary pathname completion are available at
this prompt, if you have compiled picocom with support for the
linenoise library. Pressing C-c at this prompt will cancel the file
transfer command and return to normal picocom operation. After enter‐
ing a filename (and / or additional transmission or reception program
arguments) and assuming you have not canceled the operation by pressing
C-c, picocom will start the the external program as specified by the
--send-cmd, or --receive-cmd option, and with any filenames and addi‐
tional arguments you may have supplied. The standard input and output
of the external program will be connected to the serial port. The
standard error of the external program will be connected to the termi‐
nal which---while the program is running---will revert to canonical
mode. Pressing C-c while the external program is running will prema‐
turely terminate it (assuming that the program itself does not ignore
SIGINT), and return control to picocom. Pressing C-c at any other
time, has no special effect; the character is normally passed to the
serial port.
INPUT, OUTPUT, AND ECHO MAPPING
Using the --imap, --omap, and --emap options you can make picocom map
(tranlate, replace) certain special characters after being read from
the serial port (with --imap), before being written to the serial port
(with --omap), and before being locally echoed to the terminal (stan‐
dard output) if local echo is enabled (with --emap). These mapping
options take, each, a single argument which is a comma-separated list
of one or more of the following identifiers:
· crlf (map CR to LF),
· crcrlf (map CR to CR + LF),
· igncr (ignore CR),
· lfcr (map LF to CR),
· lfcrlf (map LF to CR + LF),
· ignlf (ignore LF),
· bsdel (map BS to DEL),
· delbs (map DEL to BS)
For example the command:
picocom--omap crlf,delbs --imap inglf,bsdel --emap crcrlf ...
will:
· Replace every CR (carriage return, 0x0d) caracter with LF (line feed,
0x0a) and every DEL (delete, 0x7f) character with BS (backspace,
0x08) before writing it to the serial port.
· Ignore (not write to the terminal) every LF character read from the
serial port, and replace every BS character read from the serial port
with DEL.
· Replace every CR character with CR and LF when echoing to the termi‐
nal (if local-echo is enabled).
AUTHOR
Written by Nick Patavalis <npat@efault.net>
AVAILABILITY
Download the latest release from: <https://github.com/npat-efault/pico‐
com/releases>
COPYRIGHT
Copyright (c) 2004-2015 Nick Patavalis
This file is part of Picocom.
Picocom is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
Picocom is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Picocom 2.1 2015-10-16 PICOCOM(1)
