picocom

PICOCOM(1) User Commands PICOCOM(1)

NAME

   picocom - minimal dumb-terminal emulation program

SYNOPSIS

   picocom [ 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 its 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.

   In effect, picocom is not an emulator per-se.  It is a simple program that opens, configures, manages a serial port (tty device) and its settings, and
   connects to it the terminal emulator you are, most likely, already using (the terminal window application, xterm, rxvt, system console, etc).

   When picocom starts it opens the tty (serial port) given as its non-option argument.  Unless the noinit option is given, it configures the port 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 port is just opened.  Following this, if standard input is a tty, picocom sets the tty to raw mode.  Then 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 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 is not given, then the serial port is reset to its original settings before exiting, and the modem control
          lines (typically DTR and RTS) are cleared (lowered) signaling a modem hangup.  If noreset is given (and hangup is not), then the serial port
          settings are not reset, and the modem control lines remain unaffected.  If both noreset and hangup are given, then the serial port settings are not
          reset, but the modem-control lines are cleared.

   C-q    Quit the program without resetting the serial port to its original settings.  Terminating with the Quit command, picocom behaves exactly as if the
          noreset option was given.  The serial port is not reset to its original settings, and the modem control lines remain unaffected or are cleared,
          subject to the hangup 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.  May not be supported on some systems.

   C-g    Toggle the RTS line.  If RTS is up, then lower it.  If it is down, then raise it.  Not supported if the flow control mode is RTS/CTS.  May not be
          supported on some systems.

   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 baudrate.  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-w    Write hex.  Picococm prompts the user for a string of hexadecimal values.  Values can be entered with or without delimeters (separators).  The
          hexadecimal values are translated to binary and sent to the port, exactly as if input at the terminal (i.e. the omap, echo and emap options are
          observed).  Example: The following sends the characters ABCD to the port.

                 C-a C-w
                 *** hex: 41 4243:44
                 *** wrote 4 bytes ***

   C-s    Send (upload) a file.  See SENDING AND RECEIVING FILES below.

   C-r    Receive (download) a file.  See SENDING AND RECEIVING FILES below.

   C-v    Show program options (like baud rate, data bits, etc) as well as the actual serial port settings.  Only the options and port settings 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.

   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 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)

   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 picocom enter command
          mode.  See also the no-escape option.  (Default: a)

   no-escape | -n
          Disables the escape character.  Picocom will never enter command-mode if this option is given.  To exit picocom, in this case, you must either close
          its standard input, or send it the TERM or INT signal.  (Default: Disabled).

   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, configure, or otherwise mess 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 their
          settings.  If required, serial port parameters can then be adjusted at run-time by commands.  See also the noreset and hangup options.  (Default:
          Disabled)

   noreset | -r
          If given, picocom will not reset the serial port when exiting.  It will just close the respective file descriptor and do nothing more.  The serial
          port settings will not be restored to their original values and, unless the hangup option is also given, the modem-control lines will not be
          affected.  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 makes picocom behave exactly as if noreset was given.  See also the hangup
          option.  (Default: Disabled)

          NOTICE: Picocom clears the modem control lines on exit by setting the HUPCL control bit of the respective port.  Picocom always sets HUPCL according
          to the noreset and hangup options.  If noreset is given and hangup is not, then HUPCL for the port is cleared and will remain so after exiting
          picocom.  If noreset is not given, or if both noreset and hangup are given, then HUPCL is set for the port and will remain so after exiting
          picocom.  This is true, regardless of the way picocom terminates (command, read zero-bytes from standard input, killed by signal, fatal error, etc),
          and regardless of the noinit option.

   hangup | -u
          If given together with noreset, picocom will not reset the serial port to its original settings on exit, but it will clear the modem control lines
          (typically DTR and RTS) to signal a modem hangup.  Without the noreset option (explicitly given, or implied by extiting with the Quit command)
          hangup has no effect (without noreset picocom always clears the modem control lines on exit, anyway).

   nolock | -l
          If given, picocom will not attempt to lock the serial port before opening it.  Normally, depending on how its 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 support 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)

   –logfile | -g
          Use specified file for logging (recording) serial input, and possibly serial output.  If the file exists, it is appended to.  Every character read
          from the serial port is written to the specified file (before input mapping is performed).  If local-echo mode is is enabled (see –echo option and C-c
          command), then every character written to the serial port (after output mapping is performed) is also logged to the same file.  (Default: no logging)

   –initstring | -t
          Send the provided string after opening and configuring the serial port.  The init string is sent exactly as if it was input at the terminal.  Sending
          the init string, picocom observes the –omap output mapping, the –echo local-echo setting, and the –emap local-echo mapping.  This feature is useful,
          for example, if the serial device needs some special magic strings to start responding.  Use echo(1) or xxd(1) to generate special characters like a
          CR or binary data.  Example:

                 picocom -t "$(echo -ne 'AAATZ\r\n')" /dev/ttyS0

          Note, that the init string is not sent if noinit is given.  (Default: empty).

   lower-rts
          Lower the RTS modem control signal after opening the serial port.  Only supported when flow-control mode is not set to RTS/CTS, ignored otherwise.
          Only supported on some systems.

          If neither lower-rts nor raise-rts are given, the state of the RTS signal, after opening and configuring the port, is system dependent.  On most
          systems the signal is raised.

   raise-rts
          Raise the RTS modem control signal after opening the serial port.  Only supported when flow-control mode is not set to RTS/CTS, ignored otherwise.
          Only supported on some systems.

          If neither raise-rts nor lower-rts are given, the state of the RTS signal, after opening and configuring the port, is system dependent.  On most
          systems the signal is raised.

   lower-dtr
          Lower the DTR control signal after opening the serial port.  Only supported on some systems.

          If neither lower-dtr nor raise-dtr are given, the state of the DTR signal, after opening and configuring the port, is system dependent.  On most
          systems the signal is raised.

   raise-dtr
          Raise the DTR control signal after opening the serial port.  Only supported on some systems.

          If neither raise-dtr nor lower-dtr are given, the state of the DTR signal, after opening and configuring the port, is system dependent.  On most
          systems the signal is raised.

   exit-aftrer | -x
          Exit picocom if it remains idle for the specified time (in milliseconds).  Picocom is considered idle if: Nothing is read (received) from the serial
          port, AND there is nothing to write (send) to the serial port, AND nothing is read from the standard input (terminal).  If exit-after is set to zero,
          then picocom exits after opening and configuring the serial port, after sending the init string (if any, see option initstring) and imediatelly when
          it becomes idle.  When exiting after being idle, picocom drains the O/S serial port ouput buffer (i.e. waits for data already written to the port to
          be transmitted) and observes the noreset and hangup options as usual.  (Default: not set).

          NOTICE: If exit-after is set, reading zero bytes from the standard input (which usually means that whatever was connected there has been closed),
          will not cause picocom to exit.  Instead, picocom will keep running, without reading from stdin, and will exit only when it becomes idle for the
          specified time, or if it is killed by a signal.  If exit-after is not set, then reading zero bytes from the standard input causes picocom to exit,
          after the contents of its output queue have been transmitted.

   exit | -X
          Exit picocom immediatelly after opening and configuring the serial port.  Do not read anything from the standard input or from the serial port.  When
          exiting the noreset and hangup options are observed as usual.  With exit and noreset (and possibly hangup) picocom can be used as a very crude
          replacement of stty(1).  If an init string is also given (see initstring option), picocom exits imediatelly after sending (writing) the init string
          to the serial port and draining the O/S serial port output buffer (i.e. waiting for data written to the port to be transmitted).  Again, nothing is
          read from the standard input, or from the serial port.  The exit option, overrides the exit-after option.  (Default: Disabled)

   quiet | -q
          Forces picocom to be quiet.  Suppresses the output of the initial status and options information, as well as any other information or messages not
          explicitly requested by the user.  Responses to user commands and any error or warning messages are still printed.

   help | -h
          Print a short help message describing the command-line options.  Picocoms version, compile-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 support 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 behavior was introduced in picocom 2.0.  Older releases displayed only the option values, not the actual serial-port settings corresponding to them.

   On startup, after the serial port is opened and configured (and assuming that neither the noinit, nor the quiet command line options have been given), the
   port settings are silently checked.  If any mismatch is detected between the requested and the actual port settings, a warning message is displayed.  You may
   then use the C-v command to determine the exact mismatch or mismatches.

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 arguments, 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.  Command-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 entering 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 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 whichwhile the program is
   runningwill revert to canonical mode.  Pressing C-c while the external program is running will prematurely 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 (translate, 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 to DEL),

    delbs (map DEL to BS)

    spchex (map special chars (< 0x20 || 0x7f), excl.  CR, LF, and TAB to hex)

    tabhex (map TAB to hex)

    crhex (map CR to hex)

    lfhex (map LF to hex)

    8bithex (map chars with 8th-bit set to hex)

    nrmhex (map normal ascii chars (0x20 <= c < 0x7f) to hex)

   The to hex mappings (???hex) replace the respective characters with their hexadecimal representation (in square brackets), like this:

          CR --> [0d]

   If more than one mappings are provided that apply to the same character, then only the first mapping, in the order listed above, is applied.

   For example the command:

          picocom --omap crlf,delbs --imap ignlf,bsdel --emap crcrlf ...

   will:

    Replace every CR (carriage return, 0x0d) character 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).

EXITING PICOCOM

   This section summarizes the conditions in which picocom terminates its operation and what happens in each such condition:

    The exit command is seen in the standard input.  That is, the escape character is seen (default C-a), followed by the exit command character (default C-x).
     In this case: The contents of the output queue (data read from the standard input, but not yet written to the port) as well as the contents of the O/S
     serial port output buffer (data already written to the port, but not yet transmitted) are discarded (flushed).  Then the serial port is reset to its
     original settings, and the modem-control lines are cleared signaling a modem reset, subject to the noreset and the hangup options.  After that picocom
     exits with a success status.

    The quit command is seen in the standard input.  That is, the escape character is seen (default C-a), followed by the quit command character (default C-q).
     The behavior in this case is similar to that of the exit command, with one difference: Picocom behaves as if the noreset option is given (regardless if it
     actualy is, or not).

    The exit option is given.  See the documentation of this option for a description of what exactly happens in this case.  Picocom exits with a success exit
     status.

    The exit-after option is given.  See the documentation of this option for a description of what exactly happens in this case.  Picocom exits with a
     success exit status.

    Zero bytes are read from the standard input.  This usually means that whatever was connected to picocoms standard input has been closed or, if a file was
     connected, then picocom has read up to the end of the file.  In this case, if the exit-after option is not given, picocom stops reading from the standard
     input, and keeps operating normally (i.e. writing to, and reading from, the serial port) until its output queue empties.  When this happens, picocom waits
     for the O/S serial port output buffer to drain and then (subject to the noreset and hangup options) resets the serial port to its initial settings,
     clears the modem-control lines, and exits.  If the exit-after option is given then, again, picocom stops reading from the standard input and continues
     operating normally but, in this case, it does so until it becomes idle for the specified amount of time, before exiting.  Picocom exits with a success exit
     status.

    Picocom is killed by the TERM or INT signal, or an unrecoverable error occurs.  In this case picocom behaves as if it had received the exit command, that
     is: The contents of the output queue and the contents of the O/S serial port output buffer are discarded (flushed).  Then, subject to the noreset and
     hangup options, the serial port is reset to its original settings, the modem control lines are cleared, and picocom exits with a failure status.

AUTHOR

   Written by Nick Patavalis <npat@efault.net>

AVAILABILITY

   Download the latest release from: <https://github.com/npat-efault/picocom/releases>

COPYRIGHT

   Copyright (c) 2003-2018 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 3.1 PICOCOM(1)