Run with `python python-awesome-dd.py help` to get usage info, I find this far more reliable than Etcher/et al for writing images

python-awesome-dd.py

#!/usr/bin/env python
#
# Copyright (c) 2014, Mike 'Fuzzy' Partin <fuzzy@fu-manchu.org>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * Neither the name of the copyright holder nor the
#       names of its contributors may be used to endorse or promote products
#       derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

###########
## Stdlib

import os
import sys
import time
import urllib2
import urlparse
from curses import wrapper

####################
## Utility classes

class HumanReadable:

    def __init__(self):
        print('HumanReadable')

    def size(self, bytes=0):
        kbyte = 1024
        mbyte = (kbyte**2)
        gbyte = (kbyte**3)
        tbyte = (kbyte**4)
        pbyte = (kbyte**5)
        ebyte = (kbyte**6)
        zbyte = (kbyte**7)

        if bytes < kbyte: 
            retv = '%dB' % int(bytes)
            return '%9s' % retv
        elif bytes >= kbyte and bytes < mbyte:
            retv = '%04.02fKB' % (float(bytes) / float(kbyte))
            return '%9s' % retv
        elif bytes >= mbyte and bytes < gbyte:
            retv = '%04.02fMB' % (float(bytes) / float(mbyte))
            return '%9s' % retv
        elif bytes >= gbyte and bytes < tbyte:
            retv = '%04.02fGB' % (float(bytes) / float(gbyte))
            return '%9s' % retv
        elif bytes >= tbyte and bytes < pbyte:
            retv = '%04.02fTB' % (float(bytes) / float(tbyte))
            return '%9s' % retv
        elif bytes >= pbyte and bytes < ebyte:
            retv = '%04.02fPB' % (float(bytes) / float(pbyte))
            return '%9s' % retv
        elif bytes >= ebyte and bytes < zbyte:
            retv = '%04.02fEB' % (float(bytes) / float(ebyte))
            return '%9s' % retv
        else:
            retv = '%04.02fZB' % (float(bytes) / float(zbyte))
            return '%9s' % retv

    def time(self, seconds=0):
        # These are for convenience
        minute = 60
        hour   = (minute**2)
        day    = (hour*24)
        week   = (day*7)
        month  = (week*4)
        year   = (month*12)

        secs, mins, hrs, days, weeks, months, years = 0, 0, 0, 0, 0, 0, 0

        if seconds > year:
            years   = (seconds / year)
            tmp     = (seconds % year)
            seconds = tmp
        if seconds > month:
            months  = (seconds / month)
            tmp     = (seconds % month)
            seconds = tmp
        if seconds > week:
            weeks   = (seconds / week)
            tmp     = (seconds % week)
            seconds = tmp
        if seconds > day:
            days    = (seconds / day)
            tmp     = (seconds % day)
            seconds = tmp
        if seconds > hour:
            hrs     = (seconds / hour)
            tmp     = (seconds % hour)
            seconds = tmp
        if seconds > minute:
            mins    = (seconds / minute)
            secs    = (seconds % minute)
        if seconds < minute:
            secs   = seconds

        if years != 0:
            return '%4dy%2dm%1dw%1dd %02d:%02d:%02d' % (
                years, months, weeks, days, hrs, mins, secs
            )
        if months != 0:
            return '%2dm%1dw%1dd %02d:%02d:%02d' % (
                months, weeks, days, hrs, mins, secs
            )
        if weeks != 0:
            return '%1dw%1dd %02d:%02d:%02d' % (
                weeks, days, hrs, mins, secs
            )
        if days != 0:
            return '%1dd %02d:%02d:%02d' % (days, hrs, mins, secs)
        
        return '%02d:%02d:%02d' % (hrs, mins, secs)

class Output(HumanReadable):
    def __init__(self):
        self.display_flag  = True
        self.display_count = None

        # This is the most portable way (across POSIX systems) to get
        # our screen size that I can find, so, screw windows. Yeah.
        wrapper(self.__setmaxyx)

    def __setmaxyx(self, stdscr):
        (self.max_y, self.max_x) = stdscr.getmaxyx()


    def display(self, inTot=None, inSz=None, outSz=None, start_time=None):
        try:
            a = self.lastupdate
        except AttributeError:
            self.lastupdate = (time.time() - 5)
            
        if inTot:
            remain  = (inTot - outSz)
            percent = (float(outSz) / float(inTot))
            elapsed = (time.time() - start_time)
            speed   = (float(outSz) / float(elapsed))
            eta     = int(remain / speed)
                
            # now build out the majority of the display string
            linest  = '%s in %s @ %s/sec [' % (
                self.size(outSz),
                self.time(elapsed),
                self.size(speed)
            )
            lineend = '] %3d%% eta %s' % (
                int(percent * 100),
                self.time(eta)
            )
            
            # now figure out how many hashmarks we need
            curlen  = (len(linest)+len(lineend))
            hashlen = (self.max_x - curlen)
            hashes  = int(hashlen * percent)
            padding = (hashlen - hashes)
                
            # and put the line together
            line    = '%s%s%s%s' % (
                linest,
                '#'*hashes,
                ' '*padding,
                lineend
            )

        else:
            line = '%s in %s @ %s/sec' % (
                self.size(outSz),
                self.time(time.time() - start_time),
                self.size((outSz / (time.time() - start_time)))
            )

        if (time.time() - self.lastupdate) >= 1 and not self.quiet:
            sys.stderr.write('%s\r' % line)
            sys.stderr.flush()
            self.lastupdate = time.time()

################
## I/O classes

class Io:
    def _validateTarget(self, target=None):
        # First lets see if this is a legit path/file
        if os.path.exists(target):
            return True
        result = urlparse.urlparse(target)
        if result.scheme in ['http', 'https', 'ftp', 'ftps', 'scp', 'sftp', 'file']:
            return True
        return False

    def close(self):
        self.target.close()

    def read(self, bsize=40960):
        return self.target.read(bsize)

    def write(self, data):
        return self.target.write(data)

    def seek(self, pos=None):
        if pos:
            return self.target.seek(pos)                

class FileIo(Io):
    def __init__(self, target=None, mode=None):
        if not self._validateTarget(target):
            mode = 'w+'
        self.target = open(target, mode)
        if self.target.name != '/dev/stdout' and self.target.name != '/dev/stdin':
            self.size  = os.stat(self.target.name).st_size
            self.pipe  = False
        else:
            self.size  = None
            self.pipe  = True

class FifoIo(FileIo):
    pass

class HttpIo(Io):
    def __init__(self, target=None):
        self._validateTarget(target)
        self.target = urllib2.urlopen(target)

class FtpIo(HttpIo):
    pass

class ScpIo(Io):
    def __init__(self, bsize=10240, skip=0):
        pass

###################
## Transfer class

class Transfer(Output):
    def __init__(
            self,
            src=None,
            dst=None,
            tsize=None,
            bsize=40960,
            count=None,
            skip=None,
            quiet=False
    ):
        Output.__init__(self)
        self.src   = src
        self.dst   = dst
        self.bsize = bsize
        self.tsize = tsize
        self.count = count # TODO: Impliment
        self.skip  = skip  # TODO: Impliment
        self.quiet = quiet
        # Lets set our total size for display purposes
        if self.count:
            self.src.size = (self.bsize * self.count)
        # if we have set our total_size via an argument, lets go ahead, and set that
        try:
            if self.tsize:
                self.src.size = self.tsize
            elif not self.tsize and not os.path.isfile(self.src.target.name):
                self.src.size = -1
        except AttributeError:
            self.src.size = int(self.src.target.headers['content-length'])
        except:
            self.src.size = -1

    def start(self):
        blocks = 0
        totsze = 0

        try:
            st     = time.time()
            buff   = self.src.read(self.bsize)
            while buff:
                if totsze <= self.src.size or self.src.size == -1:
                    self.dst.write(buff)
                    blocks += 1
                    totsze += len(buff)
                    if self.src.size != -1:
                        self.display(self.src.size, totsze, totsze, st)
                    else:
                        self.display(None, totsze, totsze, st)
                    buff    = self.src.read(self.bsize)
                else:
                    buff    = None
            time.sleep(1)
            self.display(self.src.size, self.src.size, self.src.size, st)
            print
        except KeyboardInterrupt:
            print
            sys.exit(1)

#######################
## Main program entry

if __name__ == '__main__':
    # defaults
    iput  = FileIo('/dev/stdin', 'r')
    oput  = FileIo('/dev/stdout', 'a')
    ts    = None
    bs    = 40960 # 40KB
    count = None
    skip  = None
    quiet = False

    # help documentation
    usage = '''
Usage: %s <arg> <arg> ...

Arguments:

  if=<arg>      Set the input source
     /dev/stdin        # Default
     /path/to/file     # Set a path to a file or fifo
     (f|ht)tp(s)://uri # Use a remote location via http(s)/ftp(s)          (INPUT ONLY)
     scp://u@h:f       # Use SCP to get the file                           (TODO)

  of=<arg>      Set the output destination
     /dev/stdout       # Default
     /path/to/file     # Output to a file, device, fifo, socket file, etc.

  bs=<arg>      Specify the blocksize (in bytes only: Default 40960)
  ts=<arg>      Specify the total size in bytes (for use with pipes)
  count=<arg>   Specify how many blocks to transfer
  seek=<arg>    Seek <arg> number of blocks(bs) before reading data.
  quiet         Specify no progress output.
  help          Show this help screen.

''' % os.path.basename(sys.argv[0])

    # Parse out our arguments
    for arg in sys.argv:
        # Boolean args
        if arg == 'help':
            print(usage)
            sys.exit(0)
        if arg == 'quiet':
            quiet = True
        # Option args
        if arg.find('=') != -1:
            # this is a arg=opt style option, let's see which one.
            (key, val) = arg.split('=')
            if key == 'if': # input, see if it's a file
                if os.path.isfile(val):
                    iput = FileIo(val, 'r')
                else:
                    if val.find('http'):
                        iput = HttpIo(val)
                        oput = FileIo('./%s' % os.path.basename(val))
                    elif val.find('ftp'):
                        iput = FtpIo(val)
                        oput = FileIo('./%s' % os.path.basename(val))
                        
            if key == 'of': # output, see if it's a file
                oput = FileIo(val, 'w+')
            if key == 'bs':
                bs    = int(val)
            if key == 'ts':
                ts    = int(val)
            if key == 'count':
                count = int(val)
            if key == 'skip':
                skip  = int(val)
    
    obj = Transfer(iput, oput, ts, bs, count, skip, quiet)
    obj.start()

Wow! It's been a long time since I saw that code. I'm glad you found it useful! 👍

@fuzzy This is definitely one of my favorite tools in recent memory. I've used it repeatedly for writing images to USB and SD cards and other than forgetting the proper syntax of getting to the help my only thought of improvements would be to add some unit tests to it for easier refactoring.

I've been toying with rewriting this in V (https://github.com/vlang/v) I'll update with some links as soon as it's usable