NAME¶
picocom - minimal dumb-terminal emulation program
SYNOPSIS¶
picocom [ options ] device
DESCRIPTION¶
As its name suggests,
picocom 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 "terminal-window" to allow
operator intervention in PPP connection scripts (something like the ms-windows
"open terminal window before / after dialing" feature). 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 configures
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
standard-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 standard input is
copied to the serial port.
picocom also scans its input stream for a
user-specified control character, called the "escape character"
(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 on how to change it), and then keying one for 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. This is a
new behavior implemented in v1.4. Previously picocom used to ignore the
escape-character when it was entered as a function character.
- 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-u
- Baud up. Increase the baud-rate. The list of baud-rates
stepped-through by this command is: 300, 600, 1200, 2400, 4800, 9600,
19200, 38400, 57600, 115200.
- 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-b
- Cycle through databits-number settings (5, 6, 7, 8).
- C-c
- Toggle local-echo mode.
- C-v
- Show program options (like baud rate, data bits, etc). Only
the options that can be modified online (through commands) are shown, not
those that can only be set at the command-line.
- 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.
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" to transmit files, and
"rz" to receive, you have to say something like this:
picocom --send-cmd "sz -vv" --receive-cmd "rz -vv"
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. After that, picocom will start the the external program as specified
by the "--send-cmd", or "--receive-cmd" option, and with
any filenames and additional 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 terminal
which---while the program is running---will revert to canonical mode. Pressing
'C-c' while the external program is running will prematurely terminate it, and
return control to
picocom
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 (standard 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 --> DEL
- —
- delbs: map DEL --> 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 terminal (if local-echo is enabled).
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 | -p
- 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 parity, mode.
(Default: 'n')
- --databits | -d
- Defines the number of data bits in every character. Must be
one of: 5, 6, 7, 8
(Default: 8)
- --esacpe | -e
- Defines the character that will make picocom enter
command-mode (see description above). If 'x' is given, then C-x will make
picocom 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 meddle 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.
- --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 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.
- --nolock | -l
- If given, picocom will *not* attempt to lock the
serial port before opening it. Normally picocom attempts to get a
UUCP-style lock-file (e.g. "/var/lock/LCK..ttyS0") before
opening the port. Failing to do so, results in the program exiting after
emitting an error-message. It is possible that your picocom binary is
compiled without this option.
- --send-cmd | -s
- Specifies the external program (and any arguments to it)
that will be used for transmitting files.
Default: "sz -vv"
- --receive-cmd | -v
- Specifies the external program (and any arguments to it)
that will be used for receiving files.
(Default: "rz -vv")
- --imap
- Specifies the input character map (i.e. special characters
to be replaced when read from the serial port). Example: "--imap
crlf,delbs"
(Defaul: Empty)
- --omap
- Specifies the output character map (i.e. special characters
to be replaced before being written to serial port). Example: "--omap
crcrlf,bsdel"
(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). Example: "--emap crcrlf,bsdel"
(Defaul: delbs,crcrlf)
- --help | -h
- Print a short help message describing the command-line
options.
AUTHOR¶
picocom was written by Nick Patavalis (npat@efault.net)
AVAILABILITY¶
The latest version of "picocom" can be downloaded from:
http://code.google.com/p/picocom/