Started yet another new scheme for managing commands.

2 years ago · b2903c1490
parent 8f7a6c5647
commit b2903c1490
13 changed files with 2089 additions and 28 deletions
--- a/scripttease/exceptions.py
+++ b/scripttease/exceptions.py
@ -0,0 +1,6 @@
+class InvalidInput(Exception):
+    pass
+
+
+class UnknownCommand(Exception):
+    pass
--- a/scripttease/lib/commands/init.py
+++ b/scripttease/lib/commands/init.py
--- a/scripttease/lib/commands/base.py
+++ b/scripttease/lib/commands/base.py
@ -0,0 +1,389 @@
+# Imports
+
+from commonkit import parse_jinja_template, read_file
+from jinja2 import TemplateNotFound, TemplateError
+import logging
+import os
+
+log = logging.getLogger(__name__)
+
+# Exports
+
+__all__ = (
+    "EXCLUDED_KWARGS",
+    "run",
+    "Command",
+    "ItemizedCommand",
+    "Sudo",
+    "Template",
+)
+
+# Constants
+
+EXCLUDED_KWARGS = [
+    "cd",
+    "comment",
+    "condition",
+    "prefix",
+    "register",
+    "stop",
+    "sudo",
+    "tags",
+]
+
+# Functions
+
+
+def run(statement, **kwargs):
+    """Run any statement.
+
+    - statement (str): The statement to be executed.
+
+    """
+    kwargs.setdefault("comment", "run statement")
+    return Command(statement, **kwargs)
+
+# Classes
+
+
+class Command(object):
+
+    def __init__(self, statement, cd=None, comment=None, condition=None, prefix=None, register=None, stop=False, sudo=None, tags=None, **kwargs):
+        self.cd = cd
+        self.comment = comment
+        self.condition = condition
+        self.prefix = prefix
+        self.register = register
+        self.statement = statement
+        self.stop = stop
+        self.tags = tags or list()
+
+        if isinstance(sudo, Sudo):
+            self.sudo = sudo
+        elif type(sudo) is str:
+            self.sudo = Sudo(enabled=True, user=sudo)
+        elif sudo is True:
+            self.sudo = Sudo(enabled=True)
+        else:
+            self.sudo = Sudo()
+
+        self.options = kwargs
+
+    def __getattr__(self, item):
+        return self.options.get(item)
+
+    def __repr__(self):
+        if self.comment:
+            return "<%s %s>" % (self.__class__.__name__, self.comment)
+
+        return "<%s>" % self.__class__.__name__
+
+    def get_statement(self, cd=True, include_comment=True, include_register=True, include_stop=True):
+        """Get the full statement.
+
+        :param cd: Include the directory change, if given.
+        :type cd: bool
+
+        :param suppress_comment: Don't include the comment.
+        :type suppress_comment: bool
+
+        :rtype: str
+
+        """
+        a = list()
+
+        if cd and self.cd is not None:
+            a.append("( cd %s &&" % self.cd)
+
+        if self.prefix is not None:
+            a.append("%s &&" % self.prefix)
+
+        if self.sudo:
+            statement = "%s %s" % (self.sudo, self._get_statement())
+        else:
+            statement = self._get_statement()
+
+        a.append("%s" % statement)
+
+        if cd and self.cd is not None:
+            a.append(")")
+
+        b = list()
+        if self.comment is not None and include_comment:
+            b.append("# %s" % self.comment)
+
+        if self.condition is not None:
+            b.append("if [[ %s ]]; then %s; fi;" % (self.condition, " ".join(a)))
+        else:
+            b.append(" ".join(a))
+
+        if self.register is not None and include_register:
+            b.append("%s=$?;" % self.register)
+
+            if self.stop and include_stop:
+                b.append("if [[ $%s -gt 0 ]]; exit 1; fi;" % self.register)
+        elif self.stop and include_stop:
+            b.append("if [[ $? -gt 0 ]]; exit 1; fi;")
+        else:
+            pass
+
+        return "\n".join(b)
+
+    @property
+    def is_itemized(self):
+        """Always returns ``False``."""
+        return False
+
+    def _get_statement(self):
+        """By default, get the statement passed upon command initialization.
+
+        :rtype: str
+
+        """
+        return self.statement
+
+
+class Sudo(object):
+    """Helper class for defining sudo options."""
+
+    def __init__(self, enabled=False, user="root"):
+        """Initialize the helper.
+
+        :param enabled: Indicates sudo is enabled.
+        :type enabled: bool
+
+        :param user: The user to be invoked.
+        :type user: str
+
+        """
+        self.enabled = enabled
+        self.user = user
+
+    def __bool__(self):
+        return self.enabled
+
+    def __str__(self):
+        if self.enabled:
+            return "sudo -u %s" % self.user
+
+        return ""
+
+
+class ItemizedCommand(object):
+    """An itemized command represents multiple commands of with the same statement but different parameters."""
+
+    def __init__(self, callback, items, *args, name=None, **kwargs):
+        """Initialize the command.
+
+        :param callback: The function to be used to generate the command.
+
+        :param items: The command arguments.
+        :type items: list[str]
+
+        :param name: The name of the command from the mapping. Not used and not required for programmatic use, but
+                     automatically assigned during factory instantiation.
+        :type name: str
+
+        :param args: The itemized arguments. ``$item`` should be included.
+
+        Keyword arguments are passed to the command class upon instantiation.
+
+        """
+        self.args = args
+        self.callback = callback
+        self.items = items
+        self.kwargs = kwargs
+        self.name = name
+
+        # Set defaults for when ItemizedCommand is referenced directly before individual commands are instantiated. For
+        # example, when command filtering occurs.
+        self.kwargs.setdefault("tags", list())
+
+    def __getattr__(self, item):
+        return self.kwargs.get(item)
+
+    def __repr__(self):
+        return "<%s %s>" % (self.__class__.__name__, self.callback.__name__)
+
+    def get_commands(self):
+        """Get the commands to be executed.
+
+        :rtype: list[BaseType(Command)]
+
+        """
+        kwargs = self.kwargs.copy()
+
+        a = list()
+        for item in self.items:
+            args = list()
+            for arg in self.args:
+                args.append(arg.replace("$item", item))
+
+            command = self.callback(*args, **kwargs)
+            a.append(command)
+
+        return a
+
+    def get_statement(self, cd=True, include_comment=True, include_register=True, include_stop=True):
+        """Override to get multiple commands."""
+        kwargs = self.kwargs.copy()
+        comment = kwargs.pop("comment", "execute multiple commands")
+
+        a = list()
+        # a.append("# %s" % comment)
+
+        commands = self.get_commands()
+        for c in commands:
+            a.append(c.get_statement(cd=cd, include_comment=False, include_register=include_register, include_stop=include_stop))
+            a.append("")
+
+        return "\n".join(a)
+
+    @property
+    def is_itemized(self):
+        """Always returns ``True``."""
+        return True
+
+
+class Template(object):
+
+    PARSER_JINJA = "jinja2"
+    PARSER_PYTHON = "python"
+    PARSER_SIMPLE = "simple"
+
+    def __init__(self, source, target, backup=True, parser=PARSER_JINJA, **kwargs):
+        self.backup_enabled = backup
+        self.context = kwargs.pop("context", dict())
+        self.name = "template"
+        self.parser = parser
+        self.language = kwargs.pop("lang", None)
+        self.locations = kwargs.pop("locations", list())
+        self.source = os.path.expanduser(source)
+        self.target = target
+
+        sudo = kwargs.pop("sudo", None)
+        if isinstance(sudo, Sudo):
+            self.sudo = sudo
+        elif type(sudo) is str:
+            self.sudo = Sudo(enabled=True, user=sudo)
+        elif sudo is True:
+            self.sudo = Sudo(enabled=True)
+        else:
+            self.sudo = Sudo()
+
+        self.kwargs = kwargs
+
+    def __getattr__(self, item):
+        return self.kwargs.get(item)
+
+    def __str__(self):
+        return "template"
+
+    def get_content(self):
+        """Parse the template.
+
+        :rtype: str | None
+
+        """
+        template = self.get_template()
+
+        if self.parser == self.PARSER_SIMPLE:
+            content = read_file(template)
+            for key, value in self.context.items():
+                replace = "$%s$" % key
+                content = content.replace(replace, str(value))
+
+            return content
+
+        if self.parser == self.PARSER_PYTHON:
+            content = read_file(template)
+            return content % self.context
+
+        try:
+            return parse_jinja_template(template, self.context)
+        except TemplateNotFound:
+            log.error("Template not found: %s" % template)
+            return None
+        except TemplateError as e:
+            log.error("Could not parse %s template: %s" % (template, e))
+            return None
+
+    # noinspection PyUnusedLocal
+    def get_statement(self, cd=True, include_comment=True, include_register=True, include_stop=True):
+        lines = list()
+        if include_comment and self.comment is not None:
+            lines.append("# %s" % self.comment)
+
+        # TODO: Backing up a template's target is currently specific to bash.
+        if self.backup_enabled:
+            command = "%s mv %s %s.b" % (self.sudo, self.target, self.target)
+            lines.append('if [[ -f "%s" ]]; then %s; fi;' % (self.target, command.lstrip()))
+
+        # Get the content; e.g. parse the template.
+        content = self.get_content()
+
+        # Templates that are bash scripts will fail to write because of the shebang.
+        if content.startswith("#!"):
+            _content = content.split("\n")
+            first_line = _content.pop(0)
+            command = '%s echo "%s" > %s' % (self.sudo, first_line, self.target)
+            lines.append(command.lstrip())
+            command = "%s cat > %s << EOF" % (self.sudo, self.target)
+            lines.append(command.lstrip())
+            lines.append("\n".join(_content))
+            lines.append("EOF")
+        else:
+            command = "%s cat > %s << EOF" % (self.sudo, self.target)
+            lines.append(command.lstrip())
+            lines.append(content)
+            lines.append("EOF")
+
+        if include_register and self.register is not None:
+            lines.append("%s=$?;" % self.register)
+
+            if include_stop and self.stop:
+                lines.append("if [[ $%s -gt 0 ]]; exit 1; fi;" % self.register)
+        elif include_stop and self.stop:
+            lines.append("if [[ $? -gt 0 ]]; exit 1; fi;")
+        else:
+            pass
+
+        return "\n".join(lines)
+
+    def get_target_language(self):
+        if self.language is not None:
+            return self.language
+
+        if self.target.endswith(".conf"):
+            return "conf"
+        elif self.target.endswith(".ini"):
+            return "ini"
+        elif self.target.endswith(".php"):
+            return "php"
+        elif self.target.endswith(".py"):
+            return "python"
+        elif self.target.endswith(".sh"):
+            return "bash"
+        elif self.target.endswith(".yml"):
+            return "yaml"
+        else:
+            return "text"
+
+    def get_template(self):
+        """Get the template path.
+
+        :rtype: str
+
+        """
+        source = self.source
+        for location in self.locations:
+            _source = os.path.join(location, self.source)
+            if os.path.exists(_source):
+                return _source
+
+        return source
+
+    @property
+    def is_itemized(self):
+        # return "$item" in self.target
+        return False
--- a/scripttease/lib/commands/centos.py
+++ b/scripttease/lib/commands/centos.py
@ -0,0 +1,279 @@
+# Imports
+
+from commonkit import split_csv
+from .base import Command, Template
+from .django import DJANGO_MAPPINGS
+from .mysql import MYSQL_MAPPINGS
+from .pgsql import PGSQL_MAPPINGS
+from .posix import POSIX_MAPPINGS
+
+# Exports
+
+__all__ = (
+    "MAPPINGS",
+    "apache",
+    "apache_reload",
+    "apache_restart",
+    "apache_start",
+    "apache_stop",
+    "apache_test",
+    "command_exists",
+    "service_reload",
+    "service_restart",
+    "service_start",
+    "service_stop",
+    "system",
+    "system_install",
+    "system_reboot",
+    "system_update",
+    "system_upgrade",
+    "system_uninstall",
+    "template",
+    "user",
+)
+
+
+def command_exists(name):
+    """Indicates whether a given command exists in this overlay.
+
+    :param name: The name of the command.
+    :type name: str
+
+    :rtype: bool
+
+    """
+    return name in MAPPINGS
+
+
+def apache(op, **kwargs):
+    """Execute an Apache-related command.
+
+    - op (str): The operation to perform; reload, restart, start, stop, test.
+
+    """
+    if op == "reload":
+        return apache_reload(**kwargs)
+    elif op == "restart":
+        return apache_restart(**kwargs)
+    elif op == "start":
+        return apache_start(**kwargs)
+    elif op == "stop":
+        return apache_stop(**kwargs)
+    elif op == "test":
+        return apache_test(**kwargs)
+    else:
+        raise NameError("Unrecognized or unsupported apache operation: %s" % op)
+
+
+def apache_reload(**kwargs):
+    kwargs.setdefault("comment", "reload apache")
+    kwargs.setdefault("register", "apache_reloaded")
+
+    return Command("apachectl –k reload", **kwargs)
+
+
+def apache_restart(**kwargs):
+    kwargs.setdefault("comment", "restart apache")
+    kwargs.setdefault("register", "apache_restarted")
+
+    return Command("apachectl –k restart", **kwargs)
+
+
+def apache_start(**kwargs):
+    kwargs.setdefault("comment", "start apache")
+    kwargs.setdefault("register", "apache_started")
+
+    return Command("apachectl –k start", **kwargs)
+
+
+def apache_stop(**kwargs):
+    kwargs.setdefault("comment", "stop apache")
+
+    return Command("apachectl –k stop", **kwargs)
+
+
+def apache_test(**kwargs):
+    kwargs.setdefault("comment", "check apache configuration")
+    kwargs.setdefault("register", "apache_checks_out")
+
+    return Command("apachectl configtest", **kwargs)
+
+
+def service_reload(name, **kwargs):
+    """Reload a service.
+
+    - name (str): The service name.
+
+    """
+    kwargs.setdefault("comment", "reload %s service" % name)
+    kwargs.setdefault("register", "%s_reloaded" % name)
+
+    return Command("systemctl reload %s" % name, **kwargs)
+
+
+def service_restart(name, **kwargs):
+    """Restart a service.
+
+    - name (str): The service name.
+
+    """
+    kwargs.setdefault("comment", "restart %s service" % name)
+    kwargs.setdefault("register", "%s_restarted" % name)
+
+    return Command("ssystemctl restart %s" % name, **kwargs)
+
+
+def service_start(name, **kwargs):
+    """Start a service.
+
+    - name (str): The service name.
+
+    """
+    kwargs.setdefault("comment", "start %s service" % name)
+    kwargs.setdefault("register", "%s_started" % name)
+
+    return Command("systemctl start %s" % name, **kwargs)
+
+
+def service_stop(name, **kwargs):
+    """Stop a service.
+
+    - name (str): The service name.
+
+    """
+    kwargs.setdefault("comment", "stop %s service" % name)
+    kwargs.setdefault("register", "%s_stopped" % name)
+
+    return Command("systemctl stop %s" % name, **kwargs)
+
+
+def system(op, **kwargs):
+    """Perform a system operation.
+
+    - op (str): The operation to perform; reboot, update, upgrade.
+
+    """
+    if op == "reboot":
+        return system_reboot(**kwargs)
+    elif op == "update":
+        return system_update(**kwargs)
+    elif op == "upgrade":
+        return system_upgrade(**kwargs)
+    else:
+        raise NameError("Unrecognized or unsupported system operation: %s" % op)
+
+
+def system_install(name, **kwargs):
+    """Install a system-level package.
+
+    - name (str): The name of the package to install.
+
+    """
+    kwargs.setdefault("comment", "install system package %s" % name)
+
+    return Command("yum install -y %s" % name, **kwargs)
+
+
+def system_reboot(**kwargs):
+    kwargs.setdefault("comment", "reboot the system")
+
+    return Command("reboot", **kwargs)
+
+
+def system_uninstall(name, **kwargs):
+    """Uninstall a system-level package.
+
+    - name (str): The name of the package to uninstall.
+
+    """
+    kwargs.setdefault("comment", "remove system package %s" % name)
+
+    return Command("yum remove -y %s" % name, **kwargs)
+
+
+def system_update(**kwargs):
+    kwargs.setdefault("comment", "update system package info")
+
+    return Command("yum check-update", **kwargs)
+
+
+def system_upgrade(**kwargs):
+    kwargs.setdefault("comment", "upgrade the system")
+
+    return Command("yum update -y", **kwargs)
+
+
+def template(source, target, backup=True, parser=None, **kwargs):
+    """Create a file from a template.
+
+    - source (str): The path to the template file.
+    - target (str): The path to where the new file should be created.
+    - backup (bool): Indicates whether a backup should be made if the target file already exists.
+    - parser (str): The parser to use ``jinja`` (the default) or ``simple``.
+
+    """
+    return Template(source, target, backup=backup, parser=parser, **kwargs)
+
+
+def user(name, groups=None, home=None, op="add", password=None, **kwargs):
+    """Create or remove a user.
+
+    - name (str): The user name.
+    - groups (str | list): A list of groups to which the user should belong.
+    - home (str): The path to the user's home directory.
+    - op (str); The operation to perform; ``add`` or ``remove``.
+    - password (str): The user's password. (NOT IMPLEMENTED)
+
+    """
+    if op == "add":
+        kwargs.setdefault("comment", "create a user named %s" % name)
+
+        commands = list()
+
+        a = list()
+        a.append('adduser %s' % name)
+        if home is not None:
+            a.append("--home %s" % home)
+
+        commands.append(Command(" ".join(a), **kwargs))
+
+        if type(groups) is str:
+            groups = split_csv(groups, smart=False)
+
+        if type(groups) in [list, tuple]:
+            for group in groups:
+                commands.append(Command("gpasswd -a %s %s" % (name, group), **kwargs))
+
+        a = list()
+        for c in commands:
+            a.append(c.get_statement(include_comment=True))
+
+        return Command("\n".join(a), **kwargs)
+    elif op == "remove":
+        kwargs.setdefault("comment", "remove a user named %s" % name)
+        return Command("userdel -r %s" % name, **kwargs)
+    else:
+        raise NameError("Unsupported or unrecognized operation: %s" % op)
+
+
+MAPPINGS = {
+    'apache': apache,
+    'install': system_install,
+    'reboot': system_reboot,
+    'reload': service_reload,
+    'restart': service_restart,
+    'start': service_start,
+    'stop': service_stop,
+    'system': system,
+    'template': template,
+    'update': system_update,
+    'uninstall': system_uninstall,
+    'upgrade': system_upgrade,
+    'user': user,
+}
+
+MAPPINGS.update(COMMON_MAPPINGS)
+MAPPINGS.update(DJANGO_MAPPINGS)
+MAPPINGS.update(MYSQL_MAPPINGS)
+MAPPINGS.update(PGSQL_MAPPINGS)
+MAPPINGS.update(POSIX_MAPPINGS)
--- a/scripttease/lib/commands/django.py
+++ b/scripttease/lib/commands/django.py
@ -0,0 +1,92 @@
+"""
+[run django checks]
+django: check
+
+[export fixtures]
+django: dump lookups.Category
+
+[import fixtures]
+django: load lookups.Category
+
+[migrate the database]
+django: migrate
+
+[collect static files]
+django: static
+
+[create super user (ad hoc command)]
+django: createsuperuser root
+
+"""
+from .base import EXCLUDED_KWARGS, Command
+
+
+def django(management_command, *args, excluded_kwargs=None, **kwargs):
+    # The excluded parameters (filtered below) may vary based on implementation. We do, however, need a default.
+    excluded_kwargs = excluded_kwargs or EXCLUDED_KWARGS
+
+    # Django's management commands can have a number of options. We need to filter out internal parameters so that these
+    # are not used as options for the management command.
+    _kwargs = dict()
+    for key in excluded_kwargs:
+        if key in kwargs:
+            _kwargs[key] = kwargs.pop(key)
+
+    if 'comment' not in _kwargs:
+        _kwargs['comment'] = "run %s django management command" % management_command
+
+    a = list()
+    a.append("./manage.py %s" % management_command)
+    for key, value in kwargs.items():
+        key = key.replace("_", "-")
+        if type(value) is bool and value is True:
+            a.append("--%s" % key)
+        elif type(value) is str:
+            a.append('--%s="%s"' % (key, value))
+        else:
+            a.append('--%s=%s' % (key, value))
+
+    _args = list(args)
+    if len(_args) > 0:
+        a.append(" ".join(_args))
+
+    statement = " ".join(a)
+
+    return Command(statement, **_kwargs)
+
+
+def django_check(**kwargs):
+    kwargs.setdefault("comment", "run django checks")
+    kwargs.setdefault("register", "django_checks_out")
+    return django("check", **kwargs)
+
+
+def django_dump(target, path=None, **kwargs):
+    kwargs.setdefault("comment", "dump app/model data")
+    kwargs.setdefault("format", "json")
+    kwargs.setdefault("indent", 4)
+
+    if path is None:
+        path = "../deploy/fixtures/%s.%s" % (target, kwargs['format'])
+
+    return django("dumpdata", target, "> %s" % path, **kwargs)
+
+
+def django_load(target, path=None, **kwargs):
+    kwargs.setdefault("comment", "load app/model data")
+    input_format = kwargs.pop("format", "json")
+    if path is None:
+        path = "../deploy/fixtures/%s.%s" % (target, input_format)
+
+    return django("loaddata", path, **kwargs)
+
+
+def django_migrate(**kwargs):
+    kwargs.setdefault("comment", "apply database migrations")
+    return django("migrate", **kwargs)
+
+
+def django_static(**kwargs):
+    kwargs.setdefault("comment", "collect static files")
+    kwargs.setdefault("noinput", True)
+    return django("collectstatic", **kwargs)
--- a/scripttease/lib/commands/messages.py
+++ b/scripttease/lib/commands/messages.py
@ -0,0 +1,51 @@
+from .base import Command
+from ...exceptions import InvalidInput
+
+
+def dialog(message, height=15, title="Message", width=100, **kwargs):
+    statement = list()
+    statement.append("dialog --clear")
+    statement.append('--backtitle "%s"' % title)
+    statement.append('--msgbox "%s" %s %s;' % (message, height, width))
+    statement.append("clear;")
+
+    return Command(" ".join(statement), **kwargs)
+
+
+def echo(message, **kwargs):
+    return Command('echo "%s"' % message, **kwargs)
+
+
+def explain(message, heading=None, **kwargs):
+    kwargs['heading'] = heading
+    return Command(message, **kwargs)
+
+
+def screenshot(image, caption=None, **kwargs):
+    kwargs['caption'] = caption
+
+    return Command(image, **kwargs)
+
+
+def slack(message, url=None, **kwargs):
+    if url is None:
+        raise InvalidInput("Slack command requires a url parameter.")
+
+    statement = list()
+    statement.append("curl -X POST -H 'Content-type: application/json' --data")
+    statement.append('{"text": "%s"}' % message)
+    statement.append(url)
+
+    return Command(statement, **kwargs)
+
+
+def twist(message, title="Notice", url=None, **kwargs):
+    if url is None:
+        raise InvalidInput("Twist command requires a url parameter.")
+
+    statement = list()
+    statement.append("curl -X POST -H 'Content-type: application/json' --data")
+    statement.append('{"content": "%s", "title": "%s"' % (message, title))
+    statement.append(url)
+
+    return Command(" ".join(statement), **kwargs)
--- a/scripttease/lib/commands/mysql.py
+++ b/scripttease/lib/commands/mysql.py
@ -0,0 +1,173 @@
+from ...exceptions import InvalidInput
+from .base import EXCLUDED_KWARGS, Command
+
+
+__all__ = (
+    "mysql_create",
+    "mysql_dump",
+    "mysql_exists",
+    "mysql_load",
+    "mysql_user",
+)
+
+
+def mysql(command, *args, host="localhost", excluded_kwargs=None, password=None, port=3306, user="root", **kwargs):
+    # The excluded parameters (filtered below) may vary based on implementation. We do, however, need a default.
+    excluded_kwargs = excluded_kwargs or EXCLUDED_KWARGS
+
+    # if 'comment' not in kwargs:
+    #     kwargs['comment'] = "run %s mysql command" % command
+
+    # Allow additional command line switches to pass through?
+    # Django's management commands can have a number of options. We need to filter out internal parameters so that these
+    # are not used as options for the management command.
+    _kwargs = dict()
+    for key in excluded_kwargs:
+        if key in kwargs:
+            _kwargs[key] = kwargs.pop(key)
+
+    # MySQL commands always run without sudo because the --user may be provided.
+    _kwargs['sudo'] = False
+
+    a = list()
+
+    a.append(command)
+    a.append("--user %s --host=%s --port=%s" % (user, host, port))
+    
+    if password:
+        a.append('--password="%s"' % password)
+    
+    for key, value in kwargs.items():
+        key = key.replace("_", "-")
+        if type(value) is bool and value is True:
+            a.append("--%s" % key)
+        elif type(value) is str:
+            a.append('--%s="%s"' % (key, value))
+        else:
+            a.append('--%s=%s' % (key, value))
+
+    _args = list(args)
+    if len(_args) > 0:
+        a.append(" ".join(_args))
+
+    statement = " ".join(a)
+
+    return Command(statement, **_kwargs)
+
+
+def mysql_create(database, owner=None, **kwargs):
+    kwargs.setdefault("comment", "create mysql database")
+
+    command = mysql("mysqladmin create", database, **kwargs)
+    
+    if owner is not None:
+        grant = mysql_grant(owner, database=database, **kwargs)
+        command.statement += " && " + grant.statement
+        
+    return command
+
+
+def mysql_drop(database, **kwargs):
+    kwargs.setdefault("comment", "drop %s mysql database" % database)
+
+    return mysql("mysqladmin drop", database, **kwargs)
+
+
+def mysql_dump(database, path=None, **kwargs):
+    kwargs.setdefault("comment", "dump mysql database")
+    kwargs.setdefault("complete_inserts", True)
+
+    if path is None:
+        path = "%s.sql" % database
+
+    return mysql("mysqldump", database, "> %s" % path, **kwargs)
+
+
+def mysql_exists(database, **kwargs):
+    kwargs.setdefault("comment", "determine if %s mysql database exists" % database)
+    kwargs.setdefault("register", "%s_exists" % database)
+
+    command = mysql("mysql", **kwargs)
+    
+    sql = "SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = '%s'" % database
+    
+    command.statement += '--execute="%s"' % sql
+    
+    return command
+
+
+def mysql_grant(to, database=None, privileges="ALL", **kwargs):
+    """Grant privileges to a user.
+
+    - to (str): The user name to which privileges are granted.
+    - database (str): The database name.
+    - host (str): The database host name or IP address.
+    - password (str): The password for the user with sufficient access privileges to execute the command.
+    - port (int): The TCP port number of the MySQL service running on the host.
+    - privileges (str): The privileges to be granted.
+    - user (str): The name of the user with sufficient access privileges to execute the command.
+
+    """
+    kwargs.setdefault("comment", "grant mysql privileges to %s" % to)
+
+    host = kwargs.get("host", "localhost")
+
+    command = mysql("mysql", **kwargs)
+
+    # See https://dev.mysql.com/doc/refman/5.7/en/grant.html
+    _database = database or "*"
+    sql = "GRANT %(privileges)s ON %(database)s.* TO '%(user)s'@'%(host)s'" % {
+        'database': _database,
+        'host': host,
+        'privileges': privileges,
+        'user': to,
+    }
+    command.statement += ' --execute="%s"' % sql
+
+    return command
+
+
+def mysql_load(database, path, **kwargs):
+    kwargs.setdefault("comment", "load data into a mysql database")
+
+    return mysql("psql", database, "< %s" % path, **kwargs)
+
+
+def mysql_user(name, admin_pass=None, admin_user="root", op="create", password=None, **kwargs):
+    host = kwargs.get("host", "localhost")
+
+    if op == "create":
+        kwargs.setdefault("comment", "create %s mysql user" % name)
+
+        command = mysql("mysql", password=admin_pass, user=admin_user, **kwargs)
+
+        sql = "CREATE USER IF NOT EXISTS '%s'@'%s'" % (name, host)
+        if password is not None:
+            sql += " IDENTIFIED BY PASSWORD('%s')" % password
+
+        command.statement += ' --execute="%s"' % sql
+
+        return command
+    elif op == "drop":
+        kwargs.setdefault("comment", "remove %s mysql user" % name)
+
+        command = mysql("mysql", password=admin_pass, user=admin_user, **kwargs)
+
+        sql = "DROP USER IF EXISTS '%s'@'%s'" % (name, host)
+
+        command.statement += ' --execute="%s"' % sql
+
+        return command
+    elif op == "exists":
+        kwargs.setdefault("comment", "determine if %s mysql user exists" % name)
+        kwargs.setdefault("register", "mysql_use_exists")
+
+        command = mysql("mysql", password=admin_pass, user=admin_user, **kwargs)
+
+        sql = "SELECT EXISTS(SELECT 1 FROM mysql.user WHERE user = '%s')" % name
+
+        command.statement += ' --execute "%s"' % sql
+
+        return command
+    else:
+        raise InvalidInput("Unrecognized or unsupported MySQL user operation: %s" % op)
--- a/scripttease/lib/commands/pgsql.py
+++ b/scripttease/lib/commands/pgsql.py
@ -0,0 +1,155 @@
+"""
+[run django checks]
+django: check
+
+[export fixtures]
+django: dump lookups.Category
+
+[import fixtures]
+django: load lookups.Category
+
+[migrate the database]
+django: migrate
+
+[collect static files]
+django: static
+
+[create super user (ad hoc command)]
+django: createsuperuser root
+
+"""
+from ...exceptions import InvalidInput
+from .base import EXCLUDED_KWARGS, Command
+
+
+__all__ = (
+    "pgsql_create",
+    "pgsql_drop",
+    "pgsql_dump",
+    "pgsql_exists",
+    "pgsql_load",
+    "pgsql_user",
+)
+
+def pgsql(command, *args, host="localhost", excluded_kwargs=None, password=None, port=5432, user="postgres", **kwargs):
+    # The excluded parameters (filtered below) may vary based on implementation. We do, however, need a default.
+    excluded_kwargs = excluded_kwargs or EXCLUDED_KWARGS
+
+    # if 'comment' not in kwargs:
+    #     kwargs['comment'] = "run %s postgres command" % command
+
+    # Allow additional command line switches to pass through?
+    # Django's management commands can have a number of options. We need to filter out internal parameters so that these
+    # are not used as options for the management command.
+    _kwargs = dict()
+    for key in excluded_kwargs:
+        if key in kwargs:
+            _kwargs[key] = kwargs.pop(key)
+
+    # Postgres commands always run without sudo because the -U may be provided.
+    _kwargs['sudo'] = False
+
+    a = list()
+
+    if password is not None:
+        a.append('export PGPASSWORD="%s" &&' % password)
+
+    a.append(command)
+    a.append("-U %s --host=%s --port=%s" % (user, host, port))
+    for key, value in kwargs.items():
+        key = key.replace("_", "-")
+        if type(value) is bool and value is True:
+            a.append("--%s" % key)
+        elif type(value) is str:
+            a.append('--%s="%s"' % (key, value))
+        else:
+            a.append('--%s=%s' % (key, value))
+
+    _args = list(args)
+    if len(_args) > 0:
+        a.append(" ".join(_args))
+
+    statement = " ".join(a)
+
+    return Command(statement, **_kwargs)
+
+
+def pgsql_create(database, owner=None, template=None, **kwargs):
+    kwargs.setdefault("comment", "create %s postgres database" % database)
+
+    if owner is not None:
+        kwargs['owner'] = owner
+
+    if template is not None:
+        kwargs['template'] = template
+
+    return pgsql("createdb", database, **kwargs)
+
+
+def pgsql_drop(database, **kwargs):
+    kwargs.setdefault("comment", "drop %s postgres database" % database)
+
+    return pgsql("dropdb", database, **kwargs)
+
+
+def pgsql_dump(database, path=None, **kwargs):
+    kwargs.setdefault("comment", "dump postgres database")
+    kwargs.setdefault("column_inserts", True)
+
+    if path is None:
+        path = "%s.sql" % database
+
+    kwargs['dbname'] = database
+    kwargs['file'] = path
+
+    return pgsql("pg_dump", **kwargs)
+
+
+def pgsql_exists(database, **kwargs):
+    kwargs.setdefault("comment", "determine if %s postgres database exists" % database)
+    kwargs.setdefault("register", "%s_exists" % database)
+
+    command = pgsql("psql", **kwargs)
+    command.statement += r" -lqt | cut -d \| -f 1 | grep -qw %s" % database
+
+    return command
+
+
+def pgsql_load(database, path, **kwargs):
+    kwargs.setdefault("comment", "load data into a postgres database")
+
+    kwargs['dbname'] = database
+    kwargs['file'] = path
+
+    return pgsql("psql", **kwargs)
+
+
+def pgsql_user(name, admin_pass=None, admin_user="postgres", op="create", password=None, **kwargs):
+    if op == "create":
+        kwargs.setdefault("comment", "create %s postgres user" % name)
+
+        command = pgsql("createuser", "-DRS %s" % name, password=admin_pass, user=admin_user, **kwargs)
+
+        if password is not None:
+            extra = pgsql("psql", password=admin_pass, user=admin_user, **kwargs)
+            command.statement += " && " + extra.statement
+            command.statement += " -c \"ALTER USER %s WITH ENCRYPTED PASSWORD '%s';\"" % (name, password)
+
+        return command
+    elif op == "drop":
+        kwargs.setdefault("comment", "remove %s postgres user" % name)
+
+        return pgsql("dropuser", name, password=admin_pass, user=admin_user, **kwargs)
+    elif op == "exists":
+        kwargs.setdefault("comment", "determine if %s postgres user exists" % name)
+        kwargs.setdefault("register", "pgsql_use_exists")
+
+        command = pgsql("psql", password=admin_pass, user=admin_user, **kwargs)
+
+        sql = "SELECT 1 FROM pgsql_roles WHERE rolname='%s'" % name
+
+        command.statement += ' -c "%s"' % sql
+
+        return command
+    else:
+        raise InvalidInput("Unrecognized or unsupported Postgres user operation: %s" % op)
--- a/scripttease/lib/commands/posix.py
+++ b/scripttease/lib/commands/posix.py
@ -0,0 +1,532 @@
+import os
+from .base import Command
+
+
+def append(path, content=None, **kwargs):
+    """Append content to a file.
+
+    - path (str): The path to the file.
+    - content (str): The content to be appended.
+
+    """
+    kwargs.setdefault("comment", "append to %s" % path)
+
+    statement = 'echo "%s" >> %s' % (content or "", path)
+
+    return Command(statement, **kwargs)
+
+
+def archive(from_path, absolute=False, exclude=None, file_name="archive.tgz", strip=None, to_path=".", view=False,
+            **kwargs):
+    """Create a file archive.
+
+    - from_path (str): The path that should be archived.
+    - absolute (bool): Set to ``True`` to preserve the leading slash.
+    - exclude (str): A pattern to be excluded from the archive.
+    - strip (int): Remove the specified number of leading elements from the path.
+    - to_path (str): Where the archive should be created. This should *not* include the file name.
+    - view (bool): View the output of the command as it happens.
+
+    """
+    tokens = ["tar"]
+    switches = ["-cz"]
+
+    if absolute:
+        switches.append("P")
+
+    if view:
+        switches.append("v")
+
+    tokens.append("".join(switches))
+
+    if exclude:
+        tokens.append("--exclude %s" % exclude)
+
+    if strip:
+        tokens.append("--strip-components %s" % strip)
+
+    to_path = "%s/%s" % (to_path, file_name)
+    tokens.append('-f %s %s' % (to_path, from_path))
+
+    name = " ".join(tokens)
+
+    return Command(name, **kwargs)
+
+
+def certbot(domain_name, email=None, webroot=None, **kwargs):
+    """Get new SSL certificate from Let's Encrypt.
+
+    - domain_name (str): The domain name for which the SSL certificate is requested.
+    - email (str): The email address of the requester sent to the certificate authority. Required.
+    - webroot (str): The directory where the challenge file will be created.
+
+    """
+    _email = email or os.environ.get("SCRIPTTEASE_CERTBOT_EMAIL", None)
+    _webroot = webroot or os.path.join("/var", "www", "domains", domain_name.replace(".", "_"), "www")
+
+    if not _email:
+        raise ValueError("Email is required for certbot command.")
+
+    template = "certbot certonly --agree-tos --email %(email)s -n --webroot -w %(webroot)s -d %(domain_name)s"
+    statement = template % {
+        'domain_name': domain_name,
+        'email': _email,
+        'webroot': _webroot,
+    }
+
+    return Command(statement, **kwargs)
+
+
+def copy(from_path, to_path, overwrite=False, recursive=False, **kwargs):
+    """Copy a file or directory.
+
+    - from_path (str): The file or directory to be copied.
+    - to_path (str): The location to which the file or directory should be copied.
+    - overwrite (bool): Indicates files and directories should be overwritten if they exist.
+    - recursive (bool): Copy sub-directories.
+
+    """
+    kwargs.setdefault("comment", "copy %s to %s" % (from_path, to_path))
+
+    a = list()
+    a.append("cp")
+
+    if not overwrite:
+        a.append("-n")
+
+    if recursive:
+        a.append("-R")
+
+    a.append(from_path)
+    a.append(to_path)
+
+    return Command(" ".join(a), **kwargs)
+
+
+def dir(path, group=None, mode=None, owner=None, recursive=True, **kwargs):
+    """Create a directory.
+
+    - path (str): The path to be created.
+    - mode (int | str): The access permissions of the new directory.
+    - recursive (bool): Create all directories along the path.
+
+    """
+    kwargs.setdefault("comment", "create directory %s" % path)
+
+    statement = ["mkdir"]
+    if mode is not None:
+        statement.append("-m %s" % mode)
+
+    if recursive:
+        statement.append("-p")
+
+    if group:
+        if recursive:
+            statement.append("&& chgrp -R %s" % group)
+        else:
+            statement.append("&& chgrp %s" % group)
+
+    if owner:
+        if recursive:
+            statement.append("&& chown -R %s" % owner)
+        else:
+            statement.append("&& chown %s" % owner)
+
+    statement.append(path)
+
+    return Command(" ".join(statement), **kwargs)
+
+
+def extract(from_path, absolute=False, exclude=None, strip=None, to_path=None, view=False, **kwargs):
+    """Extract a file archive.
+
+    - from_path (str): The path that should be archived.
+    - absolute (bool): Set to ``True`` to preserve the leading slash.
+    - exclude (str): A pattern to be excluded from the archive.
+    - strip (int): Remove the specified number of leading elements from the path.
+    - to_path (str): Where the archive should be extracted. This should *not* include the file name.
+    - view (bool): View the output of the command as it happens.
+
+    """
+    _to_path = to_path or "./"
+
+    tokens = ["tar"]
+    switches = ["-xz"]
+
+    if absolute:
+        switches.append("P")
+
+    if view:
+        switches.append("v")
+
+    tokens.append("".join(switches))
+
+    if exclude:
+        tokens.append("--exclude %s" % exclude)
+
+    if strip:
+        tokens.append("--strip-components %s" % strip)
+
+    tokens.append('-f %s %s' % (from_path, _to_path))
+
+    statement = " ".join(tokens)
+
+    return Command(statement, **kwargs)
+
+
+def link(source, force=False, target=None, **kwargs):
+    """Create a symlink.
+
+    - source (str): The source of the link.
+    - force (bool): Force the creation of the link.
+    - target (str): The name or path of the target. Defaults to the base name of the source path.
+
+    """
+    _target = target or os.path.basename(source)
+
+    kwargs.setdefault("comment", "link to %s" % source)
+
+    statement = ["ln -s"]
+
+    if force:
+        statement.append("-f")
+
+    statement.append(source)
+    statement.append(_target)
+
+    return Command(" ".join(statement), **kwargs)
+
+
+def move(from_path, to_path, **kwargs):
+    """Move a file or directory.
+
+    - from_path (str): The current path.
+    - to_path (str): The new path.
+
+    """
+    kwargs.setdefault("comment", "move %s to %s" % (from_path, to_path))
+    statement = "mv %s %s" % (from_path, to_path)
+
+    return Command(statement, **kwargs)
+
+
+def perms(path, group=None, mode=None, owner=None, recursive=False, **kwargs):
+    """Set permissions on a file or directory.
+
+    - path (str): The path to be changed.
+    - group (str): The name of the group to be applied.
+    - mode (int | str): The access permissions of the file or directory.
+    - owner (str): The name of the user to be applied.
+    - recursive: Create all directories along the path.
+
+    """
+    commands = list()
+
+    kwargs['comment'] = "set permissions on %s" % path
+
+    if group is not None:
+        statement = ["chgrp"]
+
+        if recursive:
+            statement.append("-R")
+
+        statement.append(group)
+        statement.append(path)
+
+        commands.append(Command(" ".join(statement), **kwargs))
+
+    if owner is not None:
+        statement = ["chown"]
+
+        if recursive:
+            statement.append("-R")
+
+        statement.append(owner)
+        statement.append(path)
+
+        commands.append(Command(" ".join(statement), **kwargs))
+
+    if mode is not None:
+        statement = ["chmod"]
+
+        if recursive:
+            statement.append("-R")
+
+        statement.append(str(mode))
+        statement.append(path)
+
+        commands.append(Command(" ".join(statement), **kwargs))
+
+    kwargs.setdefault("comment", "set permissions on %s" % path)
+
+    a = list()
+    for c in commands:
+        a.append(c.get_statement(include_comment=True))
+
+    return Command("\n".join(a), **kwargs)
+
+
+def remove(path, force=False, recursive=False, **kwargs):
+    """Remove a file or directory.
+
+    - path (str): The path to be removed.
+    - force (bool): Force the removal.
+    - recursive (bool): Remove all directories along the path.
+
+    """
+    kwargs.setdefault("comment", "remove %s" % path)
+
+    statement = ["rm"]
+
+    if force:
+        statement.append("-f")
+
+    if recursive:
+        statement.append("-r")
+
+    statement.append(path)
+
+    return Command(" ".join(statement), **kwargs)
+
+
+def replace(path, backup=".b", delimiter="/", find=None, replace=None, **kwargs):
+    """Find and replace text in a file.
+
+    - path (str): The path to the file to be edited.
+    - backup (str): The backup file extension to use.
+    - delimiter (str): The pattern delimiter.
+    - find (str): The old text. Required.
+    - replace (str): The new text. Required.
+
+    """
+
+    kwargs.setdefault("comment", "find and replace in %s" % path)
+
+    context = {
+        'backup': backup,
+        'delimiter': delimiter,
+        'path': path,
+        'pattern': find,
+        'replace': replace,
+    }
+
+    template = "sed -i %(backup)s 's%(delimiter)s%(pattern)s%(delimiter)s%(replace)s%(delimiter)sg' %(path)s"
+
+    statement = template % context
+
+    return Command(statement, **kwargs)
+
+
+def rsync(source, target, delete=False, exclude=None, host=None, key_file=None, links=True, port=22,
+          recursive=True, user=None, **kwargs):
+    """Synchronize a directory structure.
+
+    - source (str): The source directory.
+    - target (str): The target directory.
+    - delete (bool): Indicates target files that exist in source but not in target should be removed.
+    - exclude (str): The path to an exclude file.
+    - host (str): The host name or IP address. This causes the command to run over SSH.
+    - key_file (str): The privacy SSH key (path) for remote connections. User expansion is automatically applied.
+    - links (bool): Include symlinks in the sync.
+    - port (int): The SSH port to use for remote connections.
+    - recursive (bool): Indicates source contents should be recursively synchronized.
+    - user (str): The user name to use for remote connections.
+
+    """
+    # - guess: When ``True``, the ``host``, ``key_file``, and ``user`` will be guessed based on the base name of
+    #               the source path.
+    # :type guess: bool
+    # if guess:
+    #     host = host or os.path.basename(source).replace("_", ".")
+    #     key_file = key_file or os.path.expanduser(os.path.join("~/.ssh", os.path.basename(source)))
+    #     user = user or os.path.basename(source)
+    # else:
+    #     host = host
+    #     key_file = key_file
+    #     user = user
+
+    kwargs.setdefault("comment", "sync %s with %s" % (source, target))
+
+    # rsync -e "ssh -i $(SSH_KEY) -p $(SSH_PORT)" -P -rvzc --delete
+    # $(OUTPUTH_PATH) $(SSH_USER)@$(SSH_HOST):$(UPLOAD_PATH) --cvs-exclude;
+
+    tokens = list()
+    tokens.append("rsync")
+    tokens.append("--cvs-exclude")
+    tokens.append("--checksum")
+    tokens.append("--compress")
+
+    if links:
+        tokens.append("--copy-links")
+
+    if delete:
+        tokens.append("--delete")
+
+    if exclude is not None:
+        tokens.append("--exclude-from=%s" % exclude)
+
+    # --partial and --progress
+    tokens.append("-P")
+
+    if recursive:
+        tokens.append("--recursive")
+
+    tokens.append(source)
+
+    conditions = [
+        host is not None,
+        key_file is not None,
+        user is not None,
+    ]
+    if all(conditions):
+        tokens.append('-e "ssh -i %s -p %s"' % (key_file, port))
+        tokens.append("%s@%s:%s" % (user, host, target))
+    else:
+        tokens.append(target)
+
+    statement = " ".join(tokens)
+
+    return Command(statement, **kwargs)
+
+
+def scopy(from_path, to_path, host=None, key_file=None, port=22, user=None, **kwargs):
+    """Copy a file or directory to a remote server.
+
+    - from_path (str): The source directory.
+    - to_path (str): The target directory.
+    - host (str): The host name or IP address. Required.
+    - key_file (str): The privacy SSH key (path) for remote connections. User expansion is automatically applied.
+    - port (int): The SSH port to use for remote connections.
+    - user (str): The user name to use for remote connections.
+
+    """
+    kwargs.setdefault("comment", "copy %s to remote %s" % (from_path, to_path))
+
+    # TODO: What to do to force local versus remote commands?
+    # kwargs['local'] = True
+
+    kwargs['sudo'] = False
+
+    statement = ["scp"]
+
+    if key_file is not None:
+        statement.append("-i %s" % key_file)
+
+    statement.append("-P %s" % port)
+    statement.append(from_path)
+
+    if host is not None and user is not None:
+        statement.append("%s@%s:%s" % (user, host, to_path))
+    elif host is not None:
+        statement.append("%s:%s" % (host, to_path))
+    else:
+        raise ValueError("Host is a required keyword argument.")
+
+    return Command(" ".join(statement), **kwargs)
+
+
+def sync(source, target, delete=False, exclude=None, links=True, recursive=True, **kwargs):
+    """Synchronize a local directory structure.
+
+    - source (str): The source directory.
+    - target (str): The target directory.
+    - delete (bool): Indicates target files that exist in source but not in target should be removed.
+    - exclude (str): The path to an exclude file.
+    - host (str): The host name or IP address. This causes the command to run over SSH.
+    - key_file (str): The privacy SSH key (path) for remote connections. User expansion is automatically applied.
+    - links (bool): Include symlinks in the sync.
+    - port (int): The SSH port to use for remote connections.
+    - recursive (bool): Indicates source contents should be recursively synchronized.
+    - user (str): The user name to use for remote connections.
+
+    """
+    # - guess: When ``True``, the ``host``, ``key_file``, and ``user`` will be guessed based on the base name of
+    #               the source path.
+    # :type guess: bool
+    # if guess:
+    #     host = host or os.path.basename(source).replace("_", ".")
+    #     key_file = key_file or os.path.expanduser(os.path.join("~/.ssh", os.path.basename(source)))
+    #     user = user or os.path.basename(source)
+    # else:
+    #     host = host
+    #     key_file = key_file
+    #     user = user
+
+    kwargs.setdefault("comment", "sync %s with %s" % (source, target))
+
+    # rsync -e "ssh -i $(SSH_KEY) -p $(SSH_PORT)" -P -rvzc --delete
+    # $(OUTPUTH_PATH) $(SSH_USER)@$(SSH_HOST):$(UPLOAD_PATH) --cvs-exclude;
+
+    tokens = list()
+    tokens.append("rsync")
+    tokens.append("--cvs-exclude")
+    tokens.append("--checksum")
+    tokens.append("--compress")
+
+    if links:
+        tokens.append("--copy-links")
+
+    if delete:
+        tokens.append("--delete")
+
+    if exclude is not None:
+        tokens.append("--exclude-from=%s" % exclude)
+
+    # --partial and --progress
+    tokens.append("-P")
+
+    if recursive:
+        tokens.append("--recursive")
+
+    tokens.append(source)
+    tokens.append(target)
+
+    statement = " ".join(tokens)
+
+    return Command(statement, **kwargs)
+
+
+def touch(path, **kwargs):
+    """Touch a file or directory.
+
+    - path (str): The file or directory to touch.
+
+    """
+    kwargs.setdefault("comment", "touch %s" % path)
+
+    return Command("touch %s" % path, **kwargs)
+
+
+def wait(seconds, **kwargs):
+    """Pause execution for a number of seconds.
+
+    - seconds (int): The number of seconds to wait.
+
+    """
+    kwargs.setdefault("comment", "pause for %s seconds" % seconds)
+
+    return Command("sleep %s" % seconds, **kwargs)
+
+
+def write(path, content=None, **kwargs):
+    """Write to a file.
+
+    - path (str): The file to be written.
+    - content (str): The content to be written. Note: If omitted, this command is equivalent to ``touch``.
+
+    """
+    _content = content or ""
+
+    kwargs.setdefault("comment", "write to %s" % path)
+
+    a = list()
+
+    if len(_content.split("\n")) > 1:
+        a.append("cat > %s << EOF" % path)
+        a.append(_content)
+        a.append("EOF")
+    else:
+        a.append('echo "%s" > %s' % (_content, path))
+
+    return Command(" ".join(a), **kwargs)
+
--- a/scripttease/lib/commands/python.py
+++ b/scripttease/lib/commands/python.py
@ -0,0 +1,39 @@
+from .base import Command
+
+
+def python_pip(name, op="install", upgrade=False, venv=None, version=3, **kwargs):
+    """Use pip to install or uninstall a Python package.
+
+    - name (str): The name of the package.
+    - op (str): The operation to perform; install, uninstall
+    - upgrade (bool): Upgrade an installed package.
+    - venv (str): The name of the virtual environment to load.
+    - version (int): The Python version to use, e.g. ``2`` or ``3``.
+
+    """
+    manager = "pip"
+    if version == 3:
+        manager = "pip3"
+
+    if upgrade:
+        statement = "%s install --upgrade %s" % (manager, name)
+    else:
+        statement = "%s %s %s" % (manager, op, name)
+
+    if venv is not None:
+        kwargs['prefix'] = "source %s/bin/activate" % venv
+
+    kwargs.setdefault("comment", "%s %s" % (op, name))
+
+    return Command(statement, **kwargs)
+
+
+def python_virtualenv(name, **kwargs):
+    """Create a Python virtual environment.
+
+    - name (str): The name of the environment to create.
+
+    """
+    kwargs.setdefault("comment", "create %s virtual environment" % name)
+
+    return Command("virtualenv %s" % name, **kwargs)
--- a/scripttease/lib/commands/ubuntu.py
+++ b/scripttease/lib/commands/ubuntu.py
@ -0,0 +1,337 @@
+# Imports
+
+from commonkit import split_csv
+from .base import Command, Template
+from .common import COMMON_MAPPINGS
+from .django import DJANGO_MAPPINGS
+from .mysql import MYSQL_MAPPINGS
+from .pgsql import PGSQL_MAPPINGS
+from .posix import POSIX_MAPPINGS
+
+# Exports
+
+__all__ = (
+    "MAPPINGS",
+    "apache",
+    "apache_disable_module",
+    "apache_disable_site",
+    "apache_enable_module",
+    "apache_enable_site",
+    "apache_reload",
+    "apache_restart",
+    "apache_start",
+    "apache_stop",
+    "apache_test",
+    "command_exists",
+    "service_reload",
+    "service_restart",
+    "service_start",
+    "service_stop",
+    "system",
+    "system_install",
+    "system_reboot",
+    "system_update",
+    "system_upgrade",
+    "system_uninstall",
+    "template",
+    "user",
+)
+
+
+def command_exists(name):
+    """Indicates whether a given command exists in this overlay.
+
+    :param name: The name of the command.
+    :type name: str
+
+    :rtype: bool
+
+    """
+    return name in MAPPINGS
+
+
+def apache(op, **kwargs):
+    """Execute an Apache-related command.
+
+    - op (str): The operation to perform; reload, restart, start, stop, test.
+
+    """
+    if op == "reload":
+        return apache_reload(**kwargs)
+    elif op == "restart":
+        return apache_restart(**kwargs)
+    elif op == "start":
+        return apache_start(**kwargs)
+    elif op == "stop":
+        return apache_stop(**kwargs)
+    elif op == "test":
+        return apache_test(**kwargs)
+    else:
+        raise NameError("Unrecognized or unsupported apache operation: %s" % op)
+
+
+def apache_disable_module(name, **kwargs):
+    """Disable an Apache module.
+
+    - name (str): The module name.
+
+    """
+    kwargs.setdefault("comment", "disable %s apache module" % name)
+
+    return Command("a2dismod %s" % name, **kwargs)
+
+
+def apache_disable_site(name, **kwargs):
+    """Disable an Apache site.
+
+    - name (str): The domain name.
+
+    """
+    kwargs.setdefault("comment", "disable %s apache site" % name)
+
+    return Command("a2dissite %s" % name, **kwargs)
+
+
+def apache_enable_module(name, **kwargs):
+    """Enable an Apache module.
+
+    - name (str): The module name.
+
+    """
+    kwargs.setdefault("comment", "enable %s apache module" % name)
+
+    return Command("a2enmod %s" % name, **kwargs)
+
+
+def apache_enable_site(name, **kwargs):
+    """Enable an Apache site.
+
+
+    """
+    kwargs.setdefault("comment", "enable %s apache module" % name)
+
+    return Command("a2ensite %s" % name, **kwargs)
+
+
+def apache_reload(**kwargs):
+    kwargs.setdefault("comment", "reload apache")
+    kwargs.setdefault("register", "apache_reloaded")
+
+    return Command("service apache2 reload", **kwargs)
+
+
+def apache_restart(**kwargs):
+    kwargs.setdefault("comment", "restart apache")
+    kwargs.setdefault("register", "apache_restarted")
+
+    return Command("service apache2 restart", **kwargs)
+
+
+def apache_start(**kwargs):
+    kwargs.setdefault("comment", "start apache")
+    kwargs.setdefault("register", "apache_started")
+
+    return Command("service apache2 start", **kwargs)
+
+
+def apache_stop(**kwargs):
+    kwargs.setdefault("comment", "stop apache")
+
+    return Command("service apache2 stop", **kwargs)
+
+
+def apache_test(**kwargs):
+    kwargs.setdefault("comment", "check apache configuration")
+    kwargs.setdefault("register", "apache_checks_out")
+
+    return Command("apachectl configtest", **kwargs)
+
+
+def service_reload(name, **kwargs):
+    """Reload a service.
+
+    - name (str): The service name.
+
+    """
+    kwargs.setdefault("comment", "reload %s service" % name)
+    kwargs.setdefault("register", "%s_reloaded" % name)
+
+    return Command("service %s reload" % name, **kwargs)
+
+
+def service_restart(name, **kwargs):
+    """Restart a service.
+
+    - name (str): The service name.
+
+    """
+    kwargs.setdefault("comment", "restart %s service" % name)
+    kwargs.setdefault("register", "%s_restarted" % name)
+
+    return Command("service %s restart" % name, **kwargs)
+
+
+def service_start(name, **kwargs):
+    """Start a service.
+
+    - name (str): The service name.
+
+    """
+    kwargs.setdefault("comment", "start %s service" % name)
+    kwargs.setdefault("register", "%s_started" % name)
+
+    return Command("service %s start" % name, **kwargs)
+
+
+def service_stop(name, **kwargs):
+    """Stop a service.
+
+    - name (str): The service name.
+
+    """
+    kwargs.setdefault("comment", "stop %s service" % name)
+    kwargs.setdefault("register", "%s_stopped" % name)
+
+    return Command("service %s stop" % name, **kwargs)
+
+
+def system(op, **kwargs):
+    """Perform a system operation.
+
+    - op (str): The operation to perform; reboot, update, upgrade.
+
+    """
+    if op == "reboot":
+        return system_reboot(**kwargs)
+    elif op == "update":
+        return system_update(**kwargs)
+    elif op == "upgrade":
+        return system_upgrade(**kwargs)
+    else:
+        raise NameError("Unrecognized or unsupported system operation: %s" % op)
+
+
+def system_install(name, **kwargs):
+    """Install a system-level package.
+
+    - name (str): The name of the package to install.
+
+    """
+    kwargs.setdefault("comment", "install system package %s" % name)
+
+    return Command("apt-get install -y %s" % name, **kwargs)
+
+
+def system_reboot(**kwargs):
+    kwargs.setdefault("comment", "reboot the system")
+
+    return Command("reboot", **kwargs)
+
+
+def system_uninstall(name, **kwargs):
+    """Uninstall a system-level package.
+
+    - name (str): The name of the package to uninstall.
+
+    """
+    kwargs.setdefault("comment", "remove system package %s" % name)
+
+    return Command("apt-get uninstall -y %s" % name, **kwargs)
+
+
+def system_update(**kwargs):
+    kwargs.setdefault("comment", "update system package info")
+
+    return Command("apt-get update -y", **kwargs)
+
+
+def system_upgrade(**kwargs):
+    kwargs.setdefault("comment", "upgrade the system")
+
+    return Command("apt-get upgrade -y", **kwargs)
+
+
+def template(source, target, backup=True, parser=None, **kwargs):
+    """Create a file from a template.
+
+    - source (str): The path to the template file.
+    - target (str): The path to where the new file should be created.
+    - backup (bool): Indicates whether a backup should be made if the target file already exists.
+    - parser (str): The parser to use ``jinja`` (the default) or ``simple``.
+
+    """
+    return Template(source, target, backup=backup, parser=parser, **kwargs)
+
+
+def user(name, groups=None, home=None, op="add", password=None, **kwargs):
+    """Create or remove a user.
+
+    - name (str): The user name.
+    - groups (str | list): A list of groups to which the user should belong.
+    - home (str): The path to the user's home directory.
+    - op (str); The operation to perform; ``add`` or ``remove``.
+    - password (str): The user's password. (NOT IMPLEMENTED)
+
+    """
+    if op == "add":
+        kwargs.setdefault("comment", "create a user named %s" % name)
+
+        commands = list()
+
+        # The gecos switch eliminates the prompts.
+        a = list()
+        a.append('adduser %s --disabled-password --gecos ""' % name)
+        if home is not None:
+            a.append("--home %s" % home)
+
+        commands.append(Command(" ".join(a), **kwargs))
+
+        if type(groups) is str:
+            groups = split_csv(groups, smart=False)
+
+        if type(groups) in [list, tuple]:
+            for group in groups:
+                commands.append(Command("adduser %s %s" % (name, group), **kwargs))
+
+        a = list()
+        for c in commands:
+            a.append(c.get_statement(include_comment=True))
+
+        return Command("\n".join(a), **kwargs)
+    elif op == "remove":
+        kwargs.setdefault("comment", "remove a user named %s" % name)
+        return Command("deluser %s" % name, **kwargs)
+    else:
+        raise NameError("Unsupported or unrecognized operation: %s" % op)
+
+
+MAPPINGS = {
+    'apache': apache,
+    'apache.disable_module': apache_disable_module,
+    'apache.disable_site': apache_disable_site,
+    'apache.enable_module': apache_enable_module,
+    'apache.enable_site': apache_enable_site,
+    'apache.reload': apache_reload,
+    'apache.restart': apache_restart,
+    'apache.start': apache_start,
+    'apache.stop': apache_stop,
+    'apache.test': apache_test,
+    'install': system_install,
+    'reboot': system_reboot,
+    'reload': service_reload,
+    'restart': service_restart,
+    'start': service_start,
+    'stop': service_stop,
+    'system': system,
+    'template': template,
+    'update': system_update,
+    'uninstall': system_uninstall,
+    'upgrade': system_upgrade,
+    'user': user,
+}
+
+MAPPINGS.update(COMMON_MAPPINGS)
+MAPPINGS.update(DJANGO_MAPPINGS)
+MAPPINGS.update(MYSQL_MAPPINGS)
+MAPPINGS.update(PGSQL_MAPPINGS)
+MAPPINGS.update(POSIX_MAPPINGS)
--- a/scripttease/lib/loaders/base.py
+++ b/scripttease/lib/loaders/base.py
@ -16,7 +16,7 @@ log = logging.getLogger(__name__)


 __all__ = (
-    "filter_snippets",
+    # "filter_snippets",
    "load_variables",
    "BaseLoader",
    "Snippet",
@ -26,32 +26,40 @@ __all__ = (
 # Functions


-def filter_snippets(snippets, environments=None, tags=None):
-    """Filter snippets based on the given criteria.
-
-    :param snippets: The snippets to be filtered.
-    :type snippets: list[scripttease.lib.loaders.base.Snippet]
-
-    :param environments: Environment names to be matched.
-    :type environments: list[str]
-
-    :param tags: Tag names to be matched.
-    :type tags: list[str]
-
-    """
-    filtered = list()
-    for snippet in snippets:
-        if environments is not None and len(snippet.environments) > 0:
-            if not any_list_item(environments, snippet.environments):
-                continue
-
-        if tags is not None:
-            if not any_list_item(tags, snippet.tags):
-                continue
-
-        filtered.append(snippet)
-
-    return filtered
+# def filter_commands(commands, key, value):
+#     """Filter commands based on the given criteria.
+#
+#     :param commands: The commands to be filtered.
+#     :type commands: list[scripttease.lib.commands.base.Command]
+#
+#     :param key: The attribute name to be matched.
+#     :type key: str
+#
+#     :param value: The value of the attribute.
+#
+#     """
+#     filtered = list()
+#     for command in commands:
+#         try:
+#             values = getattr(command, key)
+#         except AttributeError:
+#             continue
+#
+#         if not any_list_item(values, key):
+#             continue
+#
+#         if not any_list_item()
+#         if environments is not None and len(snippet.environments) > 0:
+#             if not any_list_item(environments, snippet.environments):
+#                 continue
+#
+#         if tags is not None:
+#             if not any_list_item(tags, snippet.tags):
+#                 continue
+#
+#         filtered.append(snippet)
+#
+#     return filtered


 def load_variables(path, env=None):
--- a/scripttease/lib/loaders/ini.py
+++ b/scripttease/lib/loaders/ini.py
@ -66,7 +66,7 @@ class INILoader(BaseLoader):
                    #     continue

                    # Arguments surrounded by quotes are considered to be one argument. All others are split into a
-                    # list to be passed to the callback. It is also possible that this is a call where no arguments are
+                    # list to be passed to the parser. It is also possible that this is a call where no arguments are
                    # present, so the whole thing is wrapped to protect against an index error. A TypeError is raised in
                    # cases where a command is provided with no positional arguments; we interpret this as True.
                    try: