File: grabserial

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grabserial 2.1.0-1
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#!/usr/bin/python
# -*- coding: utf-8 -*-
# vim: set ts=4 sw=4 et :
#
# grabserial - program to read a serial port and send the data to stdout
#
# Copyright 2006,2020 Sony Corporation
#
# This program is provided under the Gnu General Public License (GPL)
# version 2 ONLY. This program is distributed WITHOUT ANY WARRANTY.
# See the LICENSE file, which should have accompanied this program,
# for the text of the license.
#
# 2020-02-08 by Tim Bird <tim.bird@sony.com>
# Started 2006-09-07 by Tim Bird
#
# To do:
#  * support interrupting capture with Ctrl-C
#    * somewhere along the line, this feature got lost
#    * (maybe check the exception handler and threading in the main loop?)
#  * buffer output chars??
#  * add optional value to -a to limit number of restarts?
#  * restart based on received bytes?
#
# CHANGELOG:
#  2020.05.01 - Version 2.1
#   - add explicit log rotation feature (-R).  This should help
#     avoid data loss when doing a log rotation.  Previous method using
#     a restart (e.g. 'e 3600 -a') closed and reopend the serial port.
#  2020.02.08 - Version 2.0.4
#   - de-reference symlinks in device_exists()
#   - use stderr for error output, handle more errors, don't show usage on
#     errors (it's too big now)
#   - fix byte-string conversion bug introduced by command_mode changes
#     (Dang this unicode/bytecode handling in Python 3.0 is a pain!)
#   - rename instantpat to inlinepat (all logic is the same)
#     - preserve old --instantpat argument name for compatibility
#  2020.02.07 - Version 2.0.0
#   - add command mode (-C) to support using grabserial for showing
#     output from executing a single command over the serial port
#  2019.09.03 - Version 1.9.9
#   - fixed a bunch of pylint errors, and disabled some false positives
#    with inline pylint directives
#     - this included replacing some bare exceptions with UnicodeEncodeError
#  2018.08.20 - Version 1.9.8
#   - try to fix unicode handling (yet again)
#     - some work based on pull request submitted by 'modbw' on github
#   - handle EOFError during read_input, in case of pipe closure
#  2018.01.03 - Version 1.9.6
#   - add patches from Ilya Kuzmich to fix python3 issues,
#   - update test.sh with python linters and other improvements
#   - fix code to remove flake8 and pylint issues
#  2017.06.13 - Version 1.9.5 - add -a to restart after time expired or
#                               pattern matched.
#                             - add strftime arguments to -o.
#                             - add -Q to silence stdout when -o is active.
#  2016.09.29 - Version 1.9.4 - add thread for sending user input to target
#    by zqb-all on github
#  2016.09.06 - clean up tabs, and add vim modeline for 4-column tabs
#               grabserial should always run with python -tt grabserial
#  2016.08.31 - add microsecond precision when using system Time (-T) option
#  2016.08.30 - Version 1.9.3 - allow forcing the baudrate with -B
#  2016.07.01 - Version 1.9.2 - change how version is stored
#  2016.05.10 - Version 1.9.1 - allow skipping the tty check with -S
#  2016.05.10 - Version 1.9.0 - support use as a python module
#    Note that the main module routine will be grabserial.grab(args,[outputfd])
#      where args is a list of command-line-style args
#      as they would be passed using the standalone program.  e.g.
#      grabserial.grab(None, ["-d", "/dev/ttyUSB0", "-v"])
#      output from the serial port (with timing data) is sent to outputfd
#  2015.04.23 - Version 1.8.1 - remove instructions for applying LICENSE text
#    to new files, and add no-warranty language to grabserial.
#  2015.03.10 - Version 1.8.0 - add -o option for saving output to a file
#    add -T option for absolute times. Both contributed by ramaxlo
#  2015.03.10 - Version 1.7.1 - add line feed to inlinepat result line
#  2014.09.28 - Version 1.7.0 - add option for force reset for USB serial
#    contributed by John Mehaffey <mehaf@gedanken.com>
#  2014.01.07 - Version 1.6.0 - add option for exiting based on a
#    mid-line pattern (quitpat). Simeon Miteff <simeon.miteff@gmail.com>
#  2013.12.19 - Version 1.5.2 - verify Windows ports w/ serial.tools.list_ports
#   (thanks to Yegor Yefromov for the idea and code)
#  2013.12.16 - Version 1.5.1 - Change my e-mail address
#  2011.12.19 - Version 1.5.0 - add options for mid-line time capture
#    (inlinepat) and base time from launch of program instead of
#    first char seen (launchtime) - contributed by Kent Borg
#  2011-09-24 - better time output and time delta
#    Constantine Shulyupin <const@makelinux.com>
#  2008-06-02 - Version 1.1.0 add support for sending a command to
#    the serial port before grabbing output


# Use the module docstring as the usage text for the program
"""Grabserial reads data from a serial port, processes it, and outputs it.

It is much more flexible than a simple 'cat' command.
It keeps track of timing data, and can record when a pattern is seen
in the data. It can show timing data for every line received.
It can save the data to a file and can quit or restart based on a
timeout or when a pattern is seen.  It can split the data into multiple
files based on timeout or a pattern.

It supports interactive writing to the serial port during data collection.

It is useful for things like:
 1. capturing and annotating data from a serial port
 2. logging data to multiple files
 3. timing events in a stream of data
    (such as how long it takes a Linux kernel to boot)
 4. executing commands to a serial console.

Options:
    -h, --help             Print this message
    -d, --device=<devpath> Set the device to read (default '/dev/ttyS0')
    -b, --baudrate=<val>   Set the baudrate (default 115200)
    -B <val>               Force the baudrate to the indicated value
                             (grabserial won't check if the baudrate is legal)
    -w, --width=<val>      Set the data bit width (default 8)
    -p, --parity=<val>     Set the parity (default N)
    -s, --stopbits=<val>   Set the stopbits (default 1)
    -x, --xonxoff          Enable software flow control (default off)
    -r, --rtscts           Enable RTS/CTS flow control (default off)
    -f, --force-reset      Force pyserial to reset device parameters
    -e, --endtime=<secs>   End the program after the specified seconds have
                           elapsed.
    -c, --command=<cmd>    Send a command to the port before reading
    -t, --time             Print time for each line received.  The time is
                           when the first character of each line is
                           received by grabserial.
    -a, --again            Restart application after -e expires, -q is
                           triggered, or the serial device is disconnected.
    -R, --rotate=<time>    Rotate logs every <time> period. Time is in seconds.
    -T, --systime          Print system time for each line received. The time
                           is the absolute local time when the first character
                           of each line is received by grabserial.
    -F, --timeformat=<val> Specifies system time format for each received line
                           e.g. -F \"%%Y-%%m-%%d %%H:%%M:%%S.%%f\"
                           (default \"%%H:%%M:%%S.%%f\")
    -m, --match=<pat>      Specify a regular expression pattern to match to
                           set a base time.  Time values for lines after the
                           line matching the pattern will be relative to
                           this base time.
    -i, --inlinepat=<pat>  Specify a regular expression pattern to have its
                           time reported at end of run.  It works mid-line.
    -q, --quitpat=<pat>    Specify a regular expression pattern to end the
                           program.  It works mid-line.
    -l, --launchtime       Set base time from launch of program.
    -o, --output=<name>    Output data to the named file.
                           Uses: %%Y-%%m-%%dT%%H:%%M:%%S on "%%".
    -A, --append           Append (rather than overwrite) output data to the
                           file specifed with -o option
    -Q, --quiet            Silent on stdout, serial port data is only written
                           to file, if specified.
    -v, --verbose          Show verbose runtime messages
    -V, --version          Show version number and exit
    -S, --skip             Skip sanity checking of the serial device.
                           May be needed for some devices.
                           This option is required if you want grabserial to
                           continue running and attemp re-connections after
                           the serial device has been disconnected.
    -n, --nodelta          Skip printing delta between read lines.
        --crtonewline      Promote a carriage return to be treated as a
                           newline
    -C, --command-mode     Perform a single command on the serial port, and
                           omit command echo and shell prompt from output.
                           Must be used with -c and -q options, with the
                           argument to -q being interpreted as the prompt
                           returned after the command completes.

Ex: grabserial -e 30 -t -m "^Linux version.*"
This will grab serial input for 30 seconds, displaying the time for
each line, and re-setting the base time when the line starting with
"Linux version" is seen.
"""


import os
import sys
import getopt
import time
import datetime
import re

try:
    import thread
except ImportError:
    import _thread as thread

import serial

VERSION = (2, 1, 0)

verbose = 0         # pylint: disable=I0011,C0103
cmdinput = u""      # pylint: disable=I0011,C0103


def vprint(message):
    """Print message if in verbose mode."""
    if verbose:
        print(message)


def eprint(message):
    """Print message to standard error."""
    sys.stderr.write(message+'\n')


def usage():
    """Show grabserial usage help."""
    print("Usage: grabserial -d <device> [options]\n")
    print(__doc__)
    sys.exit(0)


def device_exists(device):
    """Check that the specified serial device exists."""
    if os.path.islink(device):
        device = os.path.realpath(device)
    try:
        from serial.tools import list_ports

        for port in list_ports.comports():
            if port[0] == device:
                return True

        return False
    except serial.SerialException:
        return os.path.exists(device)


def read_input():
    """Read input from stdin in a thread separate from the grab routine."""
    global cmdinput     # pylint: disable=I0011,C0103,W0603

    # NOTE: cmdinput is in unicode (to make handling similar between
    # python2 and python3)

    while 1:
        if sys.version_info < (3, 0):
            try:
                # raw_input in python 2.x returns byte string
                # decode to unicode
                cmdinput = raw_input().decode(sys.stdin.encoding)
            except EOFError:
                # if we're piping input, we want to stop trying to read
                # it when the pipe closes, or the file ends
                break
        else:
            # raw_input is gone in python3
            # https://www.python.org/dev/peps/pep-3111/
            # input() returns string in unicode already
            try:
                cmdinput = input()      # pylint: disable=I0011,W0141
            except EOFError:
                break

    # OK - no more user input, just wait for program exit
    while 1:
        time.sleep(1)


# grab - main routine to grab a serial port and time the output of each line
# takes a list of arguments, as they would have been passed in sys.argv
# that is, a list of strings.
# also can take an optional file descriptor for where to send the data
# by default, data read from the serial port is sent to sys.stdout, but
# you can specify your own (already open) file descriptor, or None.  This
# would only make sense if you specified another out_filename with
#    "-o","myoutputfilename"
# Return value: True if we should 'restart' the program
def grab(arglist, outputfd=sys.stdout):
    """Grab data from a serial port and produce formatted output.

    Arguments:
      arglist             : the list of arguments to configure the serial
                            port and control output and processing
                            (see usage help).
      outputfd (optional) : a file stream to which output should be sent.
                            Defaults to sys.stdout.

    Returns True if the grab should be restarted.  This may be the
    case if the connection was broken due to a timeout or an error
    on the serial port, and continuous recording is requested.
    """
    global verbose      # pylint: disable=I0011,C0103,W0603
    global cmdinput     # pylint: disable=I0011,C0103,W0603

    # parse the command line options
    try:
        opts, args = getopt.getopt(
            arglist,
            "hli:d:b:B:w:p:s:xrfc:taTF:m:e:o:AR:QvVq:nSC", [
                "help",
                "launchtime",
                "inlinepat=",
                "instantpat=",
                "device=",
                "baudrate=",
                "width=",
                "parity=",
                "stopbits=",
                "xonxoff",
                "rtscts",
                "force-reset",
                "command=",
                "time",
                "again",
                "systime",
                "timeformat=",
                "match=",
                "endtime=",
                "output=",
                "append",
                "rotate=",
                "quiet",
                "verbose",
                "version",
                "quitpat=",
                "nodelta",
                "skip",
                "crtonewline",
                "command-mode",
            ])
    except getopt.GetoptError as err:
        # print help info and exit
        eprint("Error parsing command line options:")
        eprint(str(err))
        eprint("Use 'grabserial -h' to get usage help")
        sys.exit(2)

    sd = serial.Serial()
    sd.port = ""
    sd.baudrate = 115200
    sd.bytesize = serial.EIGHTBITS
    sd.parity = serial.PARITY_NONE
    sd.stopbits = serial.STOPBITS_ONE
    sd.xonxoff = False
    sd.rtscts = False
    sd.dsrdtr = False
    # specify a read timeout of 1 second
    sd.timeout = 1
    force = False
    show_time = 0
    show_systime = 0
    basepat = ""
    inlinepat = ''
    quitpat = ''
    basetime = 0
    inlinetime = None
    endtime = 0
    out_filename = None
    out = None
    out_permissions = "wb"
    append = False
    command = ""
    command_mode = False
    skip_device_check = 0
    cr_to_nl = 0
    restart = False
    rotate_interval = 0
    rotate_time = 0
    quiet = False
    systime_format = "%H:%M:%S.%f"
    use_delta = True
    out_filenamehasdate = 0

    for opt, arg in opts:
        if opt in ["-h", "--help"]:
            usage()
        if opt in ["-d", "--device"]:
            device = arg
            if not skip_device_check and not device_exists(device):
                eprint("""Error: serial device '%s' does not exist, aborting.
If you think this port really exists, then try using the -S option
to skip the serial device check. (put it before the -d argument)

Use 'grabserial -h' for usage help."""
                       % device)
                sd.close()
                sys.exit(2)
            sd.port = device
        if opt in ["-b", "--baudrate"]:
            baud = int(arg)
            if baud not in sd.BAUDRATES:
                eprint("Error: invalid baud rate '%d' specified" % baud)
                eprint("Valid baud rates are: %s" % str(sd.BAUDRATES))
                eprint("You can force the baud rate using the -B option")
                sd.close()
                sys.exit(3)
            sd.baudrate = baud
        if opt == "-B":
            sd.baudrate = int(arg)
        if opt in ["-p", "--parity"]:
            par = arg.upper()
            if par not in sd.PARITIES:
                eprint("Error: invalid parity '%s' specified" % par)
                eprint("Valid parities are: %s" % str(sd.PARITIES))
                sd.close()
                sys.exit(3)
            sd.parity = par
        if opt in ["-w", "--width"]:
            width = int(arg)
            if width not in sd.BYTESIZES:
                eprint("Error: invalid data bit width '%d' specified" % width)
                eprint("Valid data bit widths are: %s" % str(sd.BYTESIZES))
                sd.close()
                sys.exit(3)
            sd.bytesize = width
        if opt in ["-s", "--stopbits"]:
            stop = int(arg)
            if stop not in sd.STOPBITS:
                eprint("Error: invalid stopbits '%d' specified" % stop)
                eprint("Valid stopbits are: %s" % str(sd.STOPBITS))
                sd.close()
                sys.exit(3)
            sd.stopbits = stop
        if opt in ["-c", "--command"]:
            command = arg
        if opt in ["-C", "--command-mode"]:
            command_mode = True
        if opt in ["-x", "--xonxoff"]:
            sd.xonxoff = True
        if opt in ["-r", "--rtscts"]:
            sd.rtscts = True
        if opt in ["-f", "--force-set"]:
            force = True
        if opt in ["-t", "--time"]:
            show_time = 1
            show_systime = 0
        if opt in ["-a", "--again"]:
            restart = True
        if opt in ["-T", "--systime"]:
            show_time = 0
            show_systime = 1
        if opt in ["-F", "--timeformat"]:
            systime_format = arg
        if opt in ["-m", "--match"]:
            basepat = arg
        if opt in ["-i", "--inlinepat", "--instantpat"]:
            # --instantpat is supported for backwards compatibility
            inlinepat = arg
        if opt in ["-q", "--quitpat"]:
            quitpat = arg
        if opt in ["-l", "--launchtime"]:
            vprint('Setting basetime to time of program launch')
            basetime = time.time()
        if opt in ["-e", "--endtime"]:
            endstr = arg
            try:
                endtime = time.time()+float(endstr)
            except ValueError:
                eprint("Error: invalid endtime %s specified" % arg)
                sd.close()
                sys.exit(3)
        if opt in ["-o", "--output"]:
            out_filename = arg
            if out_filename == "%":
                out_filename = "%Y-%m-%dT%H:%M:%S"
            if "%d" in out_filename:
                out_pattern = out_filename
                out_filenamehasdate = 1
            if "%" in out_filename:
                out_filename = datetime.datetime.now().strftime(out_filename)
        if opt in ["-A", "--append"]:
            out_permissions = "a+b"
            append = True
        if opt in ["-R", "--rotate"]:
            try:
                rotate_interval = float(arg)
            except ValueError:
                eprint("Error: invalid rotation time %s specified" % arg)
                sd.close()
                sys.exit(3)
            rotate_time = time.time() + rotate_interval

        if opt in ["-Q", "--quiet"]:
            quiet = True
        if opt in ["-v", "--verbose"]:
            verbose = 1
        if opt in ["-V", "--version"]:
            print("grabserial version %d.%d.%d" % VERSION)
            sd.close()
            sys.exit(0)
        if opt in ["-S", "--skip"]:
            skip_device_check = 1
        if opt in ["-n", "--nodelta"]:
            use_delta = False
        if opt in ["--crtonewline"]:
            cr_to_nl = 1

    if args:
        eprint("Error: unrecognized argument '%s'" % args[0])
        eprint("Use 'grabserial -h' to get usage help")
        eprint("")
        sys.exit(2)

    if command_mode:
        if not command:
            eprint("Error: Must specify a command in command-mode")
            sd.close()
            sys.exit(3)
        if not quitpat:
            eprint("Error: Must specify a quit pattern in command-mode")
            sd.close()
            sys.exit(3)
        cmd_index = 0
        cmd_done = False
        quit_index = 0
        quit_done = False
        vprint("Executing command '%s', and terminating on '%s'" %
               (command, quitpat))

    # if verbose, show what our settings are
    if sd.port:
        vprint("Opening serial port %s" % sd.port)
        vprint("%d:%d%s%s:xonxoff=%d:rtscts=%d" %
               (sd.baudrate, sd.bytesize, sd.parity, sd.stopbits,
                sd.xonxoff, sd.rtscts))
    else:
        eprint("Error: Missing serial port to read from.")
        eprint("Use 'grabserial -h' to get usage help")
        sys.exit(2)

    if endtime and not restart:
        vprint("Program set to end in %s seconds" % endstr)
    if endtime and restart:
        vprint("Program set to restart after %s seconds." % endstr)
    if show_time:
        vprint("Printing timing information for each line")
    if show_systime:
        vprint("Printing absolute timing information for each line")
    if basepat:
        vprint("Using pattern '%s' to set base time" % basepat)
    if inlinepat:
        vprint("Using inline pattern '%s' to report time of at end of run"
               % inlinepat)
    if quitpat and not restart:
        vprint("Using pattern '%s' to exit program" % quitpat)
    if quitpat and restart:
        vprint("Using pattern '%s' to restart program" % quitpat)
    if skip_device_check:
        vprint("Skipping check of serial device")
    if out_filename:
        try:
            # open in binary mode, to pass through data as unmodified
            # as possible
            out = open(out_filename, out_permissions)
            if out_filenamehasdate:
                out_opendate = datetime.date.today()
        except IOError:
            print("Can't open output file '%s'" % out_filename)
            sys.exit(1)
        if append:
            vprint("Appending data to '%s'" % out_filename)
        else:
            vprint("Saving data to '%s'" % out_filename)

    if rotate_time:
        if out_filename:
            vprint("Rotate output file every %s seconds" % rotate_interval)
        else:
            eprint("Error: Missing output filename")
            eprint("Must use -o if using a rotate interval (-R)")
            eprint("Use 'grabserial -h' to get usage help")
            sys.exit(2)
    if quiet:
        vprint("Keeping quiet on stdout")

    prev1 = 0
    linetime = 0
    newline = 1
    curline = ""
    xline = b""
    vprint("Use Control-C to stop...")

    try:
        # pyserial does not reconfigure the device if the settings
        # don't change from the previous ones.  This causes issues
        # with (at least) some USB serial converters
        # Allow user to force device reconfiguration
        if force:
            toggle = sd.xonxoff
            sd.xonxoff = not toggle
            sd.open()
            sd.close()
            sd.xonxoff = toggle

        sd.open()
        sd.flushInput()
        sd.flushOutput()

        if command:
            command += u"\n"
            sd.write(command.encode("utf8"))
            sd.flush()
    except serial.serialutil.SerialException:
        # This is the exception which is raised when you unplug the USB UART.
        # Applies to both python 2 and 3 on Linux and Windows.
        stop_reason = "grabserial stopped due to a SerialException"

    # capture stdin to send to serial port
    try:
        thread.start_new_thread(read_input, ())
    except thread.error:
        print("Error starting thread for read input\n")

    stop_reason = "grabserial stopped for an unknown reason"
    # read from the serial port until something stops the program
    while 1:
        try:
            if cmdinput:
                sd.write((cmdinput + u"\n").encode("utf8"))
                cmdinput = u""

            # read for up to 1 second
            # NOTE: x should be a byte string in both python 2 and 3
            x = sd.read(1)

            # see if we're supposed to stop yet
            if endtime and time.time() > endtime:
                stop_reason = "grabserial stopped due to time expiration"
                break

            # check for log rotation
            if rotate_time and time.time() > rotate_time:
                vprint("Time for log rotation at %s" %
                       datetime.datetime.now().strftime("%H:%M:%S.%f"))

                vprint("Closing output file: '%s'" % out_filename)
                out.close()
                out_filename = datetime.datetime.now().strftime(out_pattern)
                vprint("Opening new output file: '%s'" % out_filename)
                try:
                    out = open(out_filename, out_permissions)
                    out_opendate = datetime.date.today()
                except IOError:
                    print("Can't open output file '%s'" % out_filename)
                    sys.exit(1)

                # set up for next rotation
                rotate_time = time.time() + rotate_interval

            # if we didn't read anything, loop
            if len(x) == 0:
                continue

            # convert carriage returns to newlines.
            if x == b"\r":
                if cr_to_nl:
                    x = b"\n"
                else:
                    continue

            # set basetime to when first char is received
            if not basetime:
                basetime = time.time()

            # if outputting data to a file with a date in its name and the
            # date has changed, then close it and open a new file.
            if (out_filename
                    and out_filenamehasdate
                    and newline
                    and datetime.date.today() > out_opendate
                    and not endtime):
                vprint("Closing output file: '%s'" % out_filename)
                out.close()
                out_filename = datetime.datetime.now().strftime(out_pattern)
                vprint("Opening new output file: '%s'" % out_filename)
                try:
                    out = open(out_filename, out_permissions)
                    out_opendate = datetime.date.today()
                except IOError:
                    print("Can't open output file '%s'" % out_filename)
                    sys.exit(1)

            if show_time and newline:
                linetime = time.time()
                elapsed = linetime-basetime
                delta = elapsed-prev1
                msg = "[%4.6f %2.6f] " % (elapsed, delta)
                if not quiet:
                    if outputfd:
                        outputfd.write(msg)
                if out:
                    try:
                        out.write(msg.encode(sys.stdout.encoding))
                    except UnicodeEncodeError:
                        try:
                            out.write(msg.encode("utf8"))
                        except UnicodeEncodeError:
                            out.write(msg)

                prev1 = elapsed
                newline = 0

            if show_systime and newline:
                linetime = time.time()
                linetimestr = datetime.datetime.now().strftime(systime_format)
                elapsed = linetime-basetime
                if use_delta:
                    delta = elapsed-prev1
                    msg = "[%s %2.6f] " % (linetimestr, delta)
                else:
                    msg = "[%s] " % (linetimestr)
                if not quiet:
                    outputfd.write(msg)
                if out:
                    try:
                        out.write(msg.encode(sys.stdout.encoding))
                    except UnicodeEncodeError:
                        try:
                            out.write(msg.encode("utf8"))
                        except UnicodeEncodeError:
                            out.write(msg)

                prev1 = elapsed
                newline = 0

            out_char = x.decode("utf8", "ignore")
            # You sometimes get a decoding error if the serial port gives
            # you garbage data.  This can happen, for instance, when
            # the uart changes line speed during bootup.
            #
            # NOTE: I chose 'ignore' for decoding errors
            # because I believe the most common use case is
            # a user watching stdout from grabserial in a terminal
            # window.  You don't want to emit weird characters
            # in that case.  However, this will end up losing
            # characters that can't be decoded.  Another option
            # is 'replace', with its own set of issues.
            #
            # Note that the exact data from the serial port is
            # preserved in an output file (specified with the -o
            # parameter), so you can use that to diagnose weird
            # uart problems, if needed.

            # curline is in unicode
            curline += out_char
            xline += x

            # this is tricky! Enjoy.
            if command_mode:
                # check for data to suppress
                if not cmd_done and cmd_index == len(curline)-1:
                    if curline[cmd_index] == command[cmd_index]:
                        cmd_index += 1
                        out_char = None
                        if cmd_index >= len(command):
                            cmd_done = True
                    else:
                        # mis-match, output partial match, if any
                        # FIXTHIS - only look at first line returned by port
                        # (maybe set cmd_done when first \n is detected??)
                        if cmd_index:
                            if not quiet:
                                outputfd.write(curline)
                            if out:
                                out.write(xline)
                            # we just wrote it out, no need to do it later
                            out_char = None
                        cmd_index = 0

                if not quit_done and quit_index == len(curline)-1:
                    if curline[quit_index] == quitpat[quit_index]:
                        quit_index += 1
                        out_char = None
                        if quit_index >= len(quitpat):
                            quit_done = True
                    else:
                        # mis-match
                        if quit_index:
                            if not quiet:
                                outputfd.write(curline)
                            if out:
                                out.write(xline)
                            out_char = None
                        quit_index = 0

            # FIXTHIS - should I buffer the output here??
            if not quiet and out_char:
                # x is a bytestr
                outputfd.write(out_char)
            if out and out_char:
                # save bytestring data exactly as received from serial port
                # (ie there is no 'decode' here)
                out.write(x)

            # watch for patterns
            if inlinepat and not inlinetime and \
                    re.search(inlinepat, curline):
                # inlinepat is in curline:
                inlinetime = time.time()

            # Exit the loop if quitpat matches
            if quitpat and re.search(quitpat, curline):
                stop_reason = "grabserial stopped because quit pattern '" + \
                    quitpat + "' was found"
                break

            if x == b"\n":
                newline = 1
                if basepat and re.match(basepat, curline):
                    basetime = linetime
                    elapsed = 0
                    prev1 = 0
                curline = ""
                xline = b""
            sys.stdout.flush()
            if out:
                out.flush()

        except serial.serialutil.SerialException:
            # This is the exception which is raised when you unplug the USB
            # UART.  Applies to both python 2 and 3 on Linux and Windows.

            stop_reason = "grabserial stopped due to a SerialException"

            # We might get a Ctrl+C while we are sleeping, so catch that
            try:
                # Wait a second so we don't use excessive CPU to spin in a loop
                # when the serial device is disconnected.
                time.sleep(1)
            except KeyboardInterrupt:
                stop_reason = "grabserial stopped due to keyboard interrupt"

                # An actual error, don't restart.
                restart = False
            break
        except EnvironmentError:
            stop_reason = "grabserial stopped due to some external error"

            # An actual error.  We don't want to restart the program in this
            # case, so this function will return false.
            restart = False
            break
        except KeyboardInterrupt:
            stop_reason = "grabserial stopped due to keyboard interrupt"

            # An actual error, don't restart.
            restart = False
            break

    sd.close()
    if inlinetime:
        inlinetime_str = '%4.6f' % (inlinetime-basetime)
        msg = u'\nThe inlinepat: "%s" was matched at %s\n' % \
            (inlinepat, inlinetime_str)
        if not quiet:
            outputfd.write(msg)
            outputfd.flush()
        if out:
            try:
                out.write(msg.encode(sys.stdout.encoding))
            except UnicodeEncodeError:
                try:
                    out.write(msg.encode("utf8"))
                except UnicodeEncodeError:
                    out.write(msg)
            out.flush()

    if out:
        out.close()

    vprint(stop_reason)

    return restart


if __name__ == "__main__":
    while True:
        restart_requested = grab(sys.argv[1:])

        if restart_requested:
            vprint(
                "Restarting %s\n" %
                datetime.datetime.now().strftime("%H:%M:%S.%f"))
        else:
            break

# emacs custom variables for using tabs
# indent-tabs-mode: nil
# tab-width: 4