• Updated regular expressions in ShellCommand.shellquote() to catch the weirder edge cases (closes #26).

nigel.stanger / process_podcast

Browse code • Updated regular expressions in ShellCommand.shellquote() to catch the weirder edge cases (closes #26). Python2.7 master LAST_2.7_RELEASE
1 parent 69a65c8 commit 03bd0e669a086fb674d0a0a882a599defe2c6331 Nigel Stanger authored on 13 Oct 2016

Patch

Showing 1 changed file

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#!/usr/bin/env python import datetime import distutils.spawn import json import tempfile import os.path import re import pexpect from progress_bar import (ProgressBar) class ShellCommand(object): """A shell command. _executable contains the full path to the relevant executable. _base_options is a list of standard general options for this command. """ _executable = "" _base_options = [] _expect_patterns = [] @staticmethod def shellquote(s): """Quote a string so it can be safely pasted into the shell.""" # Note: pipes/shlex.quote() only wraps '' around things, # it doesn't do things like \( \), which we also need. regexes = [ # grouping parentheses for convert re.compile(r"^\($"), re.compile(r"^\)$"), # single quote re.compile(r"'"), # catch-all for non-word characters re.compile(r"^([\w\W]+)$")] substitutions = [r"\\(", r"\\)", r"'\''", r"'\1'"] for sub in zip(regexes, substitutions): s = sub[0].sub(sub[1], s) if s else s return s def __init__(self, input_options=[], output_options=[], quiet=False): self.input_options = input_options self.output_options = output_options self.progress = None self.process = None def __repr__(self): return "<{cls}: {cmd}>".format( cls=self.__class__.__name__, cmd=self.command_string(quote=True)) def append_input_options(self, items=[]): """Add a list of items to the end of the input options.""" self.input_options += items def prepend_input_options(self, items=[]): """Add a list of items at the front of the input options.""" self.input_options = items + self.input_options def append_output_options(self, items=[]): """Add a list of items to the end of the output options.""" self.output_options += items def prepend_output_options(self, items=[]): """Add a list of items at the front of the output options.""" self.output_options = items + self.output_options def executable_string(self, quote=False): """Return the executable as a string.""" if quote: return ShellCommand.shellquote(self._executable) else: return self._executable def argument_string(self, quote=False): """Return the list of arguments as a string.""" args = self._base_options + self.input_options + self.output_options if quote: return " ".join([ShellCommand.shellquote(a) for a in args]) else: return " ".join(args) def argument_list(self): """Return a combined list of all arguments.""" return self._base_options + self.input_options + self.output_options def command_string(self, quote=False): """Return the entire command as a string.""" return "{exe} {arg}".format(exe=self.executable_string(quote), arg=self.argument_string(quote)) def process_pattern(self, pat): """Respond to a pexpect pattern. Return True on EOF.""" return (pat == 0) def run(self): """Execute the command in a subprocess.""" self.process = pexpect.spawn(self.executable_string(), self.argument_list()) # EOF is always the first pattern. patterns = self.process.compile_pattern_list( [pexpect.EOF] + self._expect_patterns) try: while True: i = self.process.expect_list(patterns, timeout=None) if self.process_pattern(i): break except (KeyboardInterrupt): pass finally: if self.progress: self.progress.finish() self.process.close() return self.process.exitstatus def get_output(self): """Execute the command in a subprocess and return the output.""" return pexpect.run(self.command_string(quote=True)) class ConvertCommand(ShellCommand): """An ImageMagick convert command.""" _executable = distutils.spawn.find_executable("convert") _base_options = ["-density", "600", "xc:dimgrey", "null:", # dark grey background "("] def __init__(self, input_options=[], output_options=[], width=2048, height=1536): super(ConvertCommand, self).__init__(input_options, output_options) self._base_options = (["-size", "{w}x{h}".format(w=width, h=height)] + self._base_options) self.append_input_options( ["-resize", "{w}x{h}".format(w=width, h=height), "-background", "white", "-alpha", "remove", "-type", "truecolor", # force RGB (this and next line) "-define", "colorspace:auto-grayscale=off"]) self.prepend_output_options([")", "-gravity", "center", "-layers", "composite", "-flatten"]) class FFprobeCommand(ShellCommand): """An ffprobe shell command.""" _executable = distutils.spawn.find_executable("ffprobe") _base_options = ["-loglevel", "error", "-show_entries", "format:stream", "-print_format", "json"] def __init__(self, input_options=[], output_options=[]): super(FFprobeCommand, self).__init__(input_options, output_options) self.entries = None # The input file should be the last input option. assert(os.path.exists(self.input_options[-1])) self.last_modified = os.path.getmtime(self.input_options[-1]) def get_entries(self, section="stream", find_list=[]): """Fetch specified attributes from the input file.""" # Re-fetch if the file's changed since we last looked. modified = os.path.getmtime(self.input_options[-1]) if (not self.entries) or (modified > self.last_modified): js = json.loads(self.get_output()) self.entries = {"format": js["format"], "stream": js["streams"][0]} return [self.entries[section][f] for f in find_list] class FFmpegCommand(ShellCommand): """A "simple" ffmpeg shell command.""" _executable = distutils.spawn.find_executable("ffmpeg") _base_options = ["-y", "-nostdin"] class FFmpegConcatCommand(FFmpegCommand): """An ffmpeg shell command with a complex concat filter.""" _expect_patterns = [r"time=(\d\d):(\d\d):(\d\d\.\d\d)"] def __init__(self, input_options=[], output_options=[], quiet=False, max_progress=100, has_audio=False, has_video=False): super(FFmpegConcatCommand, self).__init__( input_options, output_options) self.progress = ProgressBar(max_value=max_progress, quiet=quiet) self.has_video = has_video if (self.has_video): self.prepend_output_options(["-codec:v", "h264", "-pix_fmt", "yuv420p", "-map", "[vconc]"]) self.has_audio = has_audio if (self.has_audio): self.prepend_output_options(["-codec:a", "pcm_s16le", "-ac", "1", "-map", "[anorm]"]) self.filters = [] def append_filter(self, filter): """Append a filter to the filters list.""" if (filter): self.filters.append(filter) def append_normalisation_filter(self): """Append a normalisation audio filter to the complex filter.""" if (self.has_audio): self.append_filter("[aconc] dynaudnorm=r=0.25:f=10:b=y [anorm]") def append_concat_filter(self, type, segments=[]): """Append a concat filter to the filters list""" if (len(segments) > 1): self.append_filter( "{inspecs} concat=n={n}:v={v}:a={a} [{t}conc]".format( inspecs=" ".join([s.output_stream_specifier() for s in segments]), n=len(segments), v=int(type == "v"), a=int(type == "a"), t=type)) elif (len(segments) == 1): self.append_filter( "{inspec} {a}null [{t}conc]".format( inspec=segments[0].output_stream_specifier(), a=type if type == "a" else "", t=type)) def build_complex_filter(self): """Build the complete complex filter. Filters in the filtergraph are separated by ";". """ return "{f}".format(f=";".join(self.filters)) def argument_string(self, quote=False): """Return the list of arguments as a string.""" args = (self._base_options + self.input_options + ["-filter_complex", self.build_complex_filter()] + self.output_options) if quote: return " ".join([ShellCommand.shellquote(a) for a in args]) else: return " ".join(args) def argument_list(self): """Return a combined list of all arguments.""" return (self._base_options + self.input_options + ["-filter_complex", self.build_complex_filter()] + self.output_options) def process_pattern(self, pat): """Respond to a pexpect pattern. Return True on EOF.""" if (pat == 1): elapsed = datetime.timedelta( hours=int(self.process.match.group(1)), minutes=int(self.process.match.group(2)), seconds=float(self.process.match.group(3))) self.progress.update(elapsed.total_seconds()) return (pat == 0) if (__name__ == "__main__"): print ShellCommand() print ConvertCommand(input_options=["in.pdf[12]"], output_options=["out.png"]) # FFprobeCommand expects the input file to exist. f = tempfile.NamedTemporaryFile() print FFprobeCommand(input_options=["-i", f.name]) f.close() print FFmpegCommand(input_options=["-i", "in.mov"], output_options=["out.mov"]) concat = FFmpegConcatCommand(input_options=["-i", "in.mov"], output_options=["out.mov"], has_audio=True) concat.append_normalisation_filter() print concat print "Quoting:" for s in ["foobar", "foo bar baz", "foo(bar)", "[foobar]", "foo[bar", "foo 'bar'", '"foobar"', "(", ")", "'"]: print " {s} => echo {sub}".format(s=s, sub=ShellCommand.shellquote(s)) #!/usr/bin/env python import datetime import distutils.spawn import json import os.path import re import pexpect from progress_bar import (ProgressBar) class ShellCommand(object): """A shell command. _executable contains the full path to the relevant executable. _base_options is a list of standard general options for this command. """ _executable = "" _base_options = [] _expect_patterns = [] @staticmethod def shellquote(s): """Quote a string so it can be safely pasted into the shell.""" # Note: pipes/shlex.quote() only wraps '' around things, # it doesn't do things like \( \), which we also need. regexes = [re.compile(r"\("), re.compile(r"\)"), re.compile(r"(\S+\s+[\S\s]+)"), re.compile(r"\[([^]]+)\]$")] substitutions = [r"\\(", r"\\)", r"'\1'", r"'[\1]'"] for sub in zip(regexes, substitutions): s = sub[0].sub(sub[1], s) if s else s return s def __init__(self, input_options=[], output_options=[], quiet=False): self.input_options = input_options self.output_options = output_options self.progress = None self.process = None def __repr__(self): return "<{cls}: {cmd}>".format( cls=self.__class__.__name__, cmd=self.command_string(quote=True)) def append_input_options(self, items=[]): """Add a list of items to the end of the input options.""" self.input_options += items def prepend_input_options(self, items=[]): """Add a list of items at the front of the input options.""" self.input_options = items + self.input_options def append_output_options(self, items=[]): """Add a list of items to the end of the output options.""" self.output_options += items def prepend_output_options(self, items=[]): """Add a list of items at the front of the output options.""" self.output_options = items + self.output_options def executable_string(self, quote=False): """Return the executable as a string.""" if quote: return ShellCommand.shellquote(self._executable) else: return self._executable def argument_string(self, quote=False): """Return the list of arguments as a string.""" args = self._base_options + self.input_options + self.output_options if quote: return " ".join([ShellCommand.shellquote(a) for a in args]) else: return " ".join(args) def argument_list(self): """Return a combined list of all arguments.""" return self._base_options + self.input_options + self.output_options def command_string(self, quote=False): """Return the entire command as a string.""" return "{exe} {arg}".format(exe=self.executable_string(quote), arg=self.argument_string(quote)) def process_pattern(self, pat): """Respond to a pexpect pattern. Return True on EOF.""" return (pat == 0) def run(self): """Execute the command in a subprocess.""" self.process = pexpect.spawn(self.executable_string(), self.argument_list()) # EOF is always the first pattern. patterns = self.process.compile_pattern_list( [pexpect.EOF] + self._expect_patterns) try: while True: i = self.process.expect_list(patterns, timeout=None) if self.process_pattern(i): break except (KeyboardInterrupt): pass finally: if self.progress: self.progress.finish() self.process.close() return self.process.exitstatus def get_output(self): """Execute the command in a subprocess and return the output.""" return pexpect.run(self.command_string(quote=True)) class ConvertCommand(ShellCommand): """An ImageMagick convert command.""" _executable = distutils.spawn.find_executable("convert") _base_options = ["-density", "600", "xc:dimgrey", "null:", # dark grey background "("] def __init__(self, input_options=[], output_options=[], width=2048, height=1536): super(ConvertCommand, self).__init__(input_options, output_options) self._base_options = (["-size", "{w}x{h}".format(w=width, h=height)] + self._base_options) self.append_input_options( ["-resize", "{w}x{h}".format(w=width, h=height), "-background", "white", "-alpha", "remove", "-type", "truecolor", # force RGB (this and next line) "-define", "colorspace:auto-grayscale=off"]) self.prepend_output_options([")", "-gravity", "center", "-layers", "composite", "-flatten"]) class FFprobeCommand(ShellCommand): """An ffprobe shell command.""" _executable = distutils.spawn.find_executable("ffprobe") _base_options = ["-loglevel", "error", "-show_entries", "format:stream", "-print_format", "json"] def __init__(self, input_options=[], output_options=[]): super(FFprobeCommand, self).__init__(input_options, output_options) self.entries = None # The input file should be the last input option. assert(os.path.exists(self.input_options[-1])) self.last_modified = os.path.getmtime(self.input_options[-1]) def get_entries(self, section="stream", find_list=[]): """Fetch specified attributes from the input file.""" # Re-fetch if the file's changed since we last looked. modified = os.path.getmtime(self.input_options[-1]) if (not self.entries) or (modified > self.last_modified): js = json.loads(self.get_output()) self.entries = {"format": js["format"], "stream": js["streams"][0]} return [self.entries[section][f] for f in find_list] class FFmpegCommand(ShellCommand): """A "simple" ffmpeg shell command.""" _executable = distutils.spawn.find_executable("ffmpeg") _base_options = ["-y", "-nostdin"] class FFmpegConcatCommand(FFmpegCommand): """An ffmpeg shell command with a complex concat filter.""" _expect_patterns = [r"time=(\d\d):(\d\d):(\d\d\.\d\d)"] def __init__(self, input_options=[], output_options=[], quiet=False, max_progress=100, has_audio=False, has_video=False): super(FFmpegConcatCommand, self).__init__( input_options, output_options) self.progress = ProgressBar(max_value=max_progress, quiet=quiet) self.has_video = has_video if (self.has_video): self.prepend_output_options(["-codec:v", "h264", "-pix_fmt", "yuv420p", "-map", "[vconc]"]) self.has_audio = has_audio if (self.has_audio): self.prepend_output_options(["-codec:a", "pcm_s16le", "-ac", "1", "-map", "[anorm]"]) self.filters = [] def append_filter(self, filter): """Append a filter to the filters list.""" if (filter): self.filters.append(filter) def append_normalisation_filter(self): """Append a normalisation audio filter to the complex filter.""" if (self.has_audio): self.append_filter("[aconc] dynaudnorm=r=0.25:f=10:b=y [anorm]") def append_concat_filter(self, type, segments=[]): """Append a concat filter to the filters list""" if (len(segments) > 1): self.append_filter( "{inspecs} concat=n={n}:v={v}:a={a} [{t}conc]".format( inspecs=" ".join([s.output_stream_specifier() for s in segments]), n=len(segments), v=int(type == "v"), a=int(type == "a"), t=type)) elif (len(segments) == 1): self.append_filter( "{inspec} {a}null [{t}conc]".format( inspec=segments[0].output_stream_specifier(), a=type if type == "a" else "", t=type)) def build_complex_filter(self): """Build the complete complex filter. Filters in the filtergraph are separated by ";". """ return "{f}".format(f=";".join(self.filters)) def argument_string(self, quote=False): """Return the list of arguments as a string.""" args = (self._base_options + self.input_options + ["-filter_complex", self.build_complex_filter()] + self.output_options) if quote: return " ".join([ShellCommand.shellquote(a) for a in args]) else: return " ".join(args) def argument_list(self): """Return a combined list of all arguments.""" return (self._base_options + self.input_options + ["-filter_complex", self.build_complex_filter()] + self.output_options) def process_pattern(self, pat): """Respond to a pexpect pattern. Return True on EOF.""" if (pat == 1): elapsed = datetime.timedelta( hours=int(self.process.match.group(1)), minutes=int(self.process.match.group(2)), seconds=float(self.process.match.group(3))) self.progress.update(elapsed.total_seconds()) return (pat == 0) if (__name__ == "__main__"): print ShellCommand() print ConvertCommand(input_options=["in.pdf[12]"], output_options=["out.png"]) print FFprobeCommand(input_options=["-i", "in.mov"]) print FFmpegCommand(input_options=["-i", "in.mov"], output_options=["out.mov"]) concat = FFmpegConcatCommand(input_options=["-i", "in.mov"], output_options=["out.mov"], has_audio=True) concat.append_normalisation_filter() print concat

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shell_command.py

#!/usr/bin/env python

import datetime
import distutils.spawn
import json
import tempfile
import os.path
import re

import pexpect

from progress_bar import (ProgressBar)

class ShellCommand(object):
    """A shell command.
    
    _executable contains the full path to the relevant executable.
    
    _base_options is a list of standard general options for this
    command.
    """
    _executable = ""
    _base_options = []
    _expect_patterns = []
    
    @staticmethod
    def shellquote(s):
        """Quote a string so it can be safely pasted into the shell."""
        # Note: pipes/shlex.quote() only wraps '' around things,
        # it doesn't do things like , which we also need.
        regexes = [
            # grouping parentheses for convert
            re.compile(r"^$$"), re.compile(r"^$$"),
            # single quote
            re.compile(r"'"),
            # catch-all for non-word characters
            re.compile(r"^([\w\W]+)$")]
        substitutions = [r"\$", r"\$", r"'\''", r"'\1'"]
        for sub in zip(regexes, substitutions):
            s = sub[0].sub(sub[1], s) if s else s
        return s
    
    def __init__(self, input_options=[], output_options=[], quiet=False):
        self.input_options = input_options
        self.output_options = output_options
        self.progress = None
        self.process = None
    
    def __repr__(self):
        return "<{cls}: {cmd}>".format(
            cls=self.__class__.__name__,
            cmd=self.command_string(quote=True))

def append_input_options(self, items=[]):
        """Add a list of items to the end of the input options."""
        self.input_options += items
    
    def prepend_input_options(self, items=[]):
        """Add a list of items at the front of the input options."""
        self.input_options = items + self.input_options
    
    def append_output_options(self, items=[]):
        """Add a list of items to the end of the output options."""
        self.output_options += items
    
    def prepend_output_options(self, items=[]):
        """Add a list of items at the front of the output options."""
        self.output_options = items + self.output_options
    
    def executable_string(self, quote=False):
        """Return the executable as a string."""
        if quote:
            return ShellCommand.shellquote(self._executable)
        else:
            return self._executable
    
    def argument_string(self, quote=False):
        """Return the list of arguments as a string."""
        args = self._base_options + self.input_options + self.output_options
        if quote:
            return " ".join([ShellCommand.shellquote(a) for a in args])
        else:
            return " ".join(args)
    
    def argument_list(self):
        """Return a combined list of all arguments."""
        return self._base_options + self.input_options + self.output_options
    
    def command_string(self, quote=False):
        """Return the entire command as a string."""
        return "{exe} {arg}".format(exe=self.executable_string(quote),
                                    arg=self.argument_string(quote))
    
    def process_pattern(self, pat):
        """Respond to a pexpect pattern. Return True on EOF."""
        return (pat == 0)
    
    def run(self):
        """Execute the command in a subprocess."""
        self.process = pexpect.spawn(self.executable_string(),
                                     self.argument_list())
        # EOF is *always* the first pattern.
        patterns = self.process.compile_pattern_list(
            [pexpect.EOF] + self._expect_patterns)
        try:
            while True:
                i = self.process.expect_list(patterns, timeout=None)
                if self.process_pattern(i):
                    break
        except (KeyboardInterrupt):
            pass
        finally:
            if self.progress:
                self.progress.finish()
            self.process.close()
            return self.process.exitstatus
    
    def get_output(self):
        """Execute the command in a subprocess and return the output."""
        return pexpect.run(self.command_string(quote=True))

class ConvertCommand(ShellCommand):
    """An ImageMagick convert command."""
    _executable = distutils.spawn.find_executable("convert")
    _base_options = ["-density", "600",
                     "xc:dimgrey", "null:", # dark grey background
                     "("]
    
    def __init__(self, input_options=[], output_options=[], width=2048, height=1536):
        super(ConvertCommand, self).__init__(input_options, output_options)
        self._base_options = (["-size", "{w}x{h}".format(w=width, h=height)] +
                              self._base_options)
        self.append_input_options(
            ["-resize", "{w}x{h}".format(w=width, h=height),
             "-background", "white", 
             "-alpha", "remove",
             "-type", "truecolor", # force RGB (this and next line)
             "-define", "colorspace:auto-grayscale=off"])
        self.prepend_output_options([")",
                                     "-gravity", "center",
                                     "-layers", "composite",
                                     "-flatten"])

class FFprobeCommand(ShellCommand):
    """An ffprobe shell command."""
    _executable = distutils.spawn.find_executable("ffprobe")
    _base_options = ["-loglevel", "error",
                     "-show_entries", "format:stream",
                     "-print_format", "json"]
    
    def __init__(self, input_options=[], output_options=[]):
        super(FFprobeCommand, self).__init__(input_options, output_options)
        self.entries = None
        # The input file should be the last input option.
        assert(os.path.exists(self.input_options[-1]))
        self.last_modified = os.path.getmtime(self.input_options[-1])
    
    def get_entries(self, section="stream", find_list=[]):
        """Fetch specified attributes from the input file."""
        # Re-fetch if the file's changed since we last looked.
        modified = os.path.getmtime(self.input_options[-1])
        if (not self.entries) or (modified > self.last_modified):
            js = json.loads(self.get_output())
            self.entries = {"format": js["format"], "stream": js["streams"][0]}
        return [self.entries[section][f] for f in find_list]

class FFmpegCommand(ShellCommand):
    """A "simple" ffmpeg shell command."""
    _executable = distutils.spawn.find_executable("ffmpeg")
    _base_options = ["-y", "-nostdin"]

class FFmpegConcatCommand(FFmpegCommand):
    """An ffmpeg shell command with a complex concat filter."""
    _expect_patterns = [r"time=(\d\d):(\d\d):(\d\d\.\d\d)"]
    
    def __init__(self, input_options=[], output_options=[], quiet=False,
                 max_progress=100, has_audio=False, has_video=False):
        super(FFmpegConcatCommand, self).__init__(
            input_options, output_options)
        self.progress = ProgressBar(max_value=max_progress, quiet=quiet)
        self.has_video = has_video
        if (self.has_video):
            self.prepend_output_options(["-codec:v", "h264",
                                         "-pix_fmt", "yuv420p",
                                         "-map", "[vconc]"])
        self.has_audio = has_audio
        if (self.has_audio):
            self.prepend_output_options(["-codec:a", "pcm_s16le",
                                         "-ac", "1",
                                         "-map", "[anorm]"])
        self.filters = []
    
    def append_filter(self, filter):
        """Append a filter to the filters list."""
        if (filter):
            self.filters.append(filter)
        
    def append_normalisation_filter(self):
        """Append a normalisation audio filter to the complex filter."""
        if (self.has_audio):
            self.append_filter("[aconc] dynaudnorm=r=0.25:f=10:b=y [anorm]")
    
    def append_concat_filter(self, type, segments=[]):
        """Append a concat filter to the filters list"""
        if (len(segments) > 1):
            self.append_filter(
                "{inspecs} concat=n={n}:v={v}:a={a} [{t}conc]".format(
                    inspecs=" ".join([s.output_stream_specifier()
                                      for s in segments]),
                    n=len(segments), v=int(type == "v"),
                    a=int(type == "a"), t=type))
        elif (len(segments) == 1):
            self.append_filter(
                "{inspec} {a}null [{t}conc]".format(
                    inspec=segments[0].output_stream_specifier(),
                    a=type if type == "a" else "", t=type))
        
    def build_complex_filter(self):
        """Build the complete complex filter.
        
        Filters in the filtergraph are separated by ";".
        """
        return "{f}".format(f=";".join(self.filters))
    
    def argument_string(self, quote=False):
        """Return the list of arguments as a string."""
        args = (self._base_options + self.input_options +
                ["-filter_complex", self.build_complex_filter()] +
                self.output_options)
        if quote:
            return " ".join([ShellCommand.shellquote(a) for a in args])
        else:
            return " ".join(args)
    
    def argument_list(self):
        """Return a combined list of all arguments."""
        return (self._base_options + self.input_options +
                ["-filter_complex", self.build_complex_filter()] +
                self.output_options)
    
    def process_pattern(self, pat):
        """Respond to a pexpect pattern. Return True on EOF."""
        if (pat == 1):
            elapsed = datetime.timedelta(
                hours=int(self.process.match.group(1)),
                minutes=int(self.process.match.group(2)),
                seconds=float(self.process.match.group(3)))
            self.progress.update(elapsed.total_seconds())
        return (pat == 0)

if (__name__ == "__main__"):
    print ShellCommand()
    print ConvertCommand(input_options=["in.pdf[12]"],
                         output_options=["out.png"])
    
    # FFprobeCommand expects the input file to exist.
    f = tempfile.NamedTemporaryFile()
    print FFprobeCommand(input_options=["-i", f.name])
    f.close()
        
    print FFmpegCommand(input_options=["-i", "in.mov"],
                        output_options=["out.mov"])
    concat = FFmpegConcatCommand(input_options=["-i", "in.mov"],
                                 output_options=["out.mov"], has_audio=True)
    concat.append_normalisation_filter()
    print concat
    
    print "Quoting:"
    for s in ["foobar", "foo bar baz", "foo(bar)", "[foobar]", "foo[bar",
              "foo 'bar'", '"foobar"', "(", ")", "'"]:
        print "  {s} => echo {sub}".format(s=s, sub=ShellCommand.shellquote(s))

#!/usr/bin/env python

import datetime
import distutils.spawn
import json
import os.path
import re

import pexpect

from progress_bar import (ProgressBar)

class ShellCommand(object):
    """A shell command.
    
    _executable contains the full path to the relevant executable.
    
    _base_options is a list of standard general options for this
    command.
    """
    _executable = ""
    _base_options = []
    _expect_patterns = []
    
    @staticmethod
    def shellquote(s):
        """Quote a string so it can be safely pasted into the shell."""
        # Note: pipes/shlex.quote() only wraps '' around things,
        # it doesn't do things like , which we also need.
        regexes = [re.compile(r"$"), re.compile(r"$"),
                   re.compile(r"(\S+\s+[\S\s]+)"), 
                   re.compile(r"\[([^]]+)\]$")]
        substitutions = [r"\$", r"\$", r"'\1'", r"'[\1]'"]
        for sub in zip(regexes, substitutions):
            s = sub[0].sub(sub[1], s) if s else s
        return s
    
    def __init__(self, input_options=[], output_options=[], quiet=False):
        self.input_options = input_options
        self.output_options = output_options
        self.progress = None
        self.process = None
    
    def __repr__(self):
        return "<{cls}: {cmd}>".format(
            cls=self.__class__.__name__,
            cmd=self.command_string(quote=True))

class FFmpegCommand(ShellCommand):
    """A "simple" ffmpeg shell command."""
    _executable = distutils.spawn.find_executable("ffmpeg")
    _base_options = ["-y", "-nostdin"]

if (__name__ == "__main__"):
    print ShellCommand()
    print ConvertCommand(input_options=["in.pdf[12]"], output_options=["out.png"])
    print FFprobeCommand(input_options=["-i", "in.mov"])
    print FFmpegCommand(input_options=["-i", "in.mov"],
                        output_options=["out.mov"])
    concat = FFmpegConcatCommand(input_options=["-i", "in.mov"],
                                 output_options=["out.mov"], has_audio=True)
    concat.append_normalisation_filter()
    print concat

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