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+git-multimail version 1.5.0
+===========================
+
+.. image:: https://travis-ci.org/git-multimail/git-multimail.svg?branch=master
+    :target: https://travis-ci.org/git-multimail/git-multimail
+
+git-multimail is a tool for sending notification emails on pushes to a
+Git repository.  It includes a Python module called ``git_multimail.py``,
+which can either be used as a hook script directly or can be imported
+as a Python module into another script.
+
+git-multimail is derived from the Git project's old
+contrib/hooks/post-receive-email, and is mostly compatible with that
+script.  See README.migrate-from-post-receive-email for details about
+the differences and for how to migrate from post-receive-email to
+git-multimail.
+
+git-multimail, like the rest of the Git project, is licensed under
+GPLv2 (see the COPYING file for details).
+
+Please note: although, as a convenience, git-multimail may be
+distributed along with the main Git project, development of
+git-multimail takes place in its own, separate project.  Please, read
+`<CONTRIBUTING.rst>`__ for more information.
+
+
+By default, for each push received by the repository, git-multimail:
+
+1. Outputs one email summarizing each reference that was changed.
+   These "reference change" (called "refchange" below) emails describe
+   the nature of the change (e.g., was the reference created, deleted,
+   fast-forwarded, etc.) and include a one-line summary of each commit
+   that was added to the reference.
+
+2. Outputs one email for each new commit that was introduced by the
+   reference change.  These "commit" emails include a list of the
+   files changed by the commit, followed by the diffs of files
+   modified by the commit.  The commit emails are threaded to the
+   corresponding reference change email via "In-Reply-To".  This style
+   (similar to the "git format-patch" style used on the Git mailing
+   list) makes it easy to scan through the emails, jump to patches
+   that need further attention, and write comments about specific
+   commits.  Commits are handled in reverse topological order (i.e.,
+   parents shown before children).  For example::
+
+     [git] branch master updated
+     + [git] 01/08: doc: fix xref link from api docs to manual pages
+     + [git] 02/08: api-credentials.txt: show the big picture first
+     + [git] 03/08: api-credentials.txt: mention credential.helper explicitly
+     + [git] 04/08: api-credentials.txt: add "see also" section
+     + [git] 05/08: t3510 (cherry-pick-sequence): add missing '&&'
+     + [git] 06/08: Merge branch 'rr/maint-t3510-cascade-fix'
+     + [git] 07/08: Merge branch 'mm/api-credentials-doc'
+     + [git] 08/08: Git 1.7.11-rc2
+
+   By default, each commit appears in exactly one commit email, the
+   first time that it is pushed to the repository.  If a commit is later
+   merged into another branch, then a one-line summary of the commit
+   is included in the reference change email (as usual), but no
+   additional commit email is generated. See
+   `multimailhook.refFilter(Inclusion|Exclusion|DoSend|DontSend)Regex`
+   below to configure which branches and tags are watched by the hook.
+
+   By default, reference change emails have their "Reply-To" field set
+   to the person who pushed the change, and commit emails have their
+   "Reply-To" field set to the author of the commit.
+
+3. Output one "announce" mail for each new annotated tag, including
+   information about the tag and optionally a shortlog describing the
+   changes since the previous tag.  Such emails might be useful if you
+   use annotated tags to mark releases of your project.
+
+
+Requirements
+------------
+
+* Python 2.x, version 2.4 or later.  No non-standard Python modules
+  are required.  git-multimail has preliminary support for Python 3
+  (but it has been better tested with Python 2).
+
+* The ``git`` command must be in your PATH.  git-multimail is known to
+  work with Git versions back to 1.7.1.  (Earlier versions have not
+  been tested; if you do so, please report your results.)
+
+* To send emails using the default configuration, a standard sendmail
+  program must be located at '/usr/sbin/sendmail' or
+  '/usr/lib/sendmail' and must be configured correctly to send emails.
+  If this is not the case, set multimailhook.sendmailCommand, or see
+  the multimailhook.mailer configuration variable below for how to
+  configure git-multimail to send emails via an SMTP server.
+
+* git-multimail is currently tested only on Linux. It may or may not
+  work on other platforms such as Windows and Mac OS. See
+  `<CONTRIBUTING.rst>`__ to improve the situation.
+
+
+Invocation
+----------
+
+``git_multimail.py`` is designed to be used as a ``post-receive`` hook in a
+Git repository (see githooks(5)).  Link or copy it to
+$GIT_DIR/hooks/post-receive within the repository for which email
+notifications are desired.  Usually it should be installed on the
+central repository for a project, to which all commits are eventually
+pushed.
+
+For use on pre-v1.5.1 Git servers, ``git_multimail.py`` can also work as
+an ``update`` hook, taking its arguments on the command line.  To use
+this script in this manner, link or copy it to $GIT_DIR/hooks/update.
+Please note that the script is not completely reliable in this mode
+[1]_.
+
+Alternatively, ``git_multimail.py`` can be imported as a Python module
+into your own Python post-receive script.  This method is a bit more
+work, but allows the behavior of the hook to be customized using
+arbitrary Python code.  For example, you can use a custom environment
+(perhaps inheriting from GenericEnvironment or GitoliteEnvironment) to
+
+* change how the user who did the push is determined
+
+* read users' email addresses from an LDAP server or from a database
+
+* decide which users should be notified about which commits based on
+  the contents of the commits (e.g., for users who want to be notified
+  only about changes affecting particular files or subdirectories)
+
+Or you can change how emails are sent by writing your own Mailer
+class.  The ``post-receive`` script in this directory demonstrates how
+to use ``git_multimail.py`` as a Python module.  (If you make interesting
+changes of this type, please consider sharing them with the
+community.)
+
+
+Troubleshooting/FAQ
+-------------------
+
+Please read `<doc/troubleshooting.rst>`__ for frequently asked
+questions and common issues with git-multimail.
+
+
+Configuration
+-------------
+
+By default, git-multimail mostly takes its configuration from the
+following ``git config`` settings:
+
+multimailhook.environment
+    This describes the general environment of the repository. In most
+    cases, you do not need to specify a value for this variable:
+    `git-multimail` will autodetect which environment to use.
+    Currently supported values:
+
+    generic
+      the username of the pusher is read from $USER or $USERNAME and
+      the repository name is derived from the repository's path.
+
+    gitolite
+      Environment to use when ``git-multimail`` is ran as a gitolite_
+      hook.
+
+      The username of the pusher is read from $GL_USER, the repository
+      name is read from $GL_REPO, and the From: header value is
+      optionally read from gitolite.conf (see multimailhook.from).
+
+      For more information about gitolite and git-multimail, read
+      `<doc/gitolite.rst>`__
+
+    stash
+      Environment to use when ``git-multimail`` is ran as an Atlassian
+      BitBucket Server (formerly known as Atlassian Stash) hook.
+
+      **Warning:** this mode was provided by a third-party contributor
+      and never tested by the git-multimail maintainers. It is
+      provided as-is and may or may not work for you.
+
+      This value is automatically assumed when the stash-specific
+      flags (``--stash-user`` and ``--stash-repo``) are specified on
+      the command line. When this environment is active, the username
+      and repo come from these two command line flags, which must be
+      specified.
+
+    gerrit
+      Environment to use when ``git-multimail`` is ran as a
+      ``ref-updated`` Gerrit hook.
+
+      This value is used when the gerrit-specific command line flags
+      (``--oldrev``, ``--newrev``, ``--refname``, ``--project``) for
+      gerrit's ref-updated hook are present. When this environment is
+      active, the username of the pusher is taken from the
+      ``--submitter`` argument if that command line option is passed,
+      otherwise 'Gerrit' is used. The repository name is taken from
+      the ``--project`` option on the command line, which must be passed.
+
+      For more information about gerrit and git-multimail, read
+      `<doc/gerrit.rst>`__
+
+    If none of these environments is suitable for your setup, then you
+    can implement a Python class that inherits from Environment and
+    instantiate it via a script that looks like the example
+    post-receive script.
+
+    The environment value can be specified on the command line using
+    the ``--environment`` option. If it is not specified on the
+    command line or by ``multimailhook.environment``, the value is
+    guessed as follows:
+
+    * If stash-specific (respectively gerrit-specific) command flags
+      are present on the command-line, then ``stash`` (respectively
+      ``gerrit``) is used.
+
+    * If the environment variables $GL_USER and $GL_REPO are set, then
+      ``gitolite`` is used.
+
+    * If none of the above apply, then ``generic`` is used.
+
+multimailhook.repoName
+    A short name of this Git repository, to be used in various places
+    in the notification email text.  The default is to use $GL_REPO
+    for gitolite repositories, or otherwise to derive this value from
+    the repository path name.
+
+multimailhook.mailingList
+    The list of email addresses to which notification emails should be
+    sent, as RFC 2822 email addresses separated by commas.  This
+    configuration option can be multivalued.  Leave it unset or set it
+    to the empty string to not send emails by default.  The next few
+    settings can be used to configure specific address lists for
+    specific types of notification email.
+
+multimailhook.refchangeList
+    The list of email addresses to which summary emails about
+    reference changes should be sent, as RFC 2822 email addresses
+    separated by commas.  This configuration option can be
+    multivalued.  The default is the value in
+    multimailhook.mailingList.  Set this value to "none" (or the empty
+    string) to prevent reference change emails from being sent even if
+    multimailhook.mailingList is set.
+
+multimailhook.announceList
+    The list of email addresses to which emails about new annotated
+    tags should be sent, as RFC 2822 email addresses separated by
+    commas.  This configuration option can be multivalued.  The
+    default is the value in multimailhook.refchangeList or
+    multimailhook.mailingList.  Set this value to "none" (or the empty
+    string) to prevent annotated tag announcement emails from being sent
+    even if one of the other values is set.
+
+multimailhook.commitList
+    The list of email addresses to which emails about individual new
+    commits should be sent, as RFC 2822 email addresses separated by
+    commas.  This configuration option can be multivalued.  The
+    default is the value in multimailhook.mailingList.  Set this value
+    to "none" (or the empty string) to prevent notification emails about
+    individual commits from being sent even if
+    multimailhook.mailingList is set.
+
+multimailhook.announceShortlog
+    If this option is set to true, then emails about changes to
+    annotated tags include a shortlog of changes since the previous
+    tag.  This can be useful if the annotated tags represent releases;
+    then the shortlog will be a kind of rough summary of what has
+    happened since the last release.  But if your tagging policy is
+    not so straightforward, then the shortlog might be confusing
+    rather than useful.  Default is false.
+
+multimailhook.commitEmailFormat
+    The format of email messages for the individual commits, can be "text" or
+    "html". In the latter case, the emails will include diffs using colorized
+    HTML instead of plain text used by default. Note that this  currently the
+    ref change emails are always sent in plain text.
+
+    Note that when using "html", the formatting is done by parsing the
+    output of ``git log`` with ``-p``. When using
+    ``multimailhook.commitLogOpts`` to specify a ``--format`` for
+    ``git log``, one may get false positive (e.g. lines in the body of
+    the message starting with ``+++`` or ``---`` colored in red or
+    green).
+
+    By default, all the message is HTML-escaped. See
+    ``multimailhook.htmlInIntro`` to change this behavior.
+
+multimailhook.commitBrowseURL
+    Used to generate a link to an online repository browser in commit
+    emails. This variable must be a string. Format directives like
+    ``%(<variable>)s`` will be expanded the same way as template
+    strings. In particular, ``%(id)s`` will be replaced by the full
+    Git commit identifier (40-chars hexadecimal).
+
+    If the string does not contain any format directive, then
+    ``%(id)s`` will be automatically added to the string. If you don't
+    want ``%(id)s`` to be automatically added, use the empty format
+    directive ``%()s`` anywhere in the string.
+
+    For example, a suitable value for the git-multimail project itself
+    would be
+    ``https://github.com/git-multimail/git-multimail/commit/%(id)s``.
+
+multimailhook.htmlInIntro, multimailhook.htmlInFooter
+    When generating an HTML message, git-multimail escapes any HTML
+    sequence by default. This means that if a template contains HTML
+    like ``<a href="foo">link</a>``, the reader will see the HTML
+    source code and not a proper link.
+
+    Set ``multimailhook.htmlInIntro`` to true to allow writing HTML
+    formatting in introduction templates. Similarly, set
+    ``multimailhook.htmlInFooter`` for HTML in the footer.
+
+    Variables expanded in the template are still escaped. For example,
+    if a repository's path contains a ``<``, it will be rendered as
+    such in the message.
+
+    Read `<doc/customizing-emails.rst>`__ for more details and
+    examples.
+
+multimailhook.refchangeShowGraph
+    If this option is set to true, then summary emails about reference
+    changes will additionally include:
+
+    * a graph of the added commits (if any)
+
+    * a graph of the discarded commits (if any)
+
+    The log is generated by running ``git log --graph`` with the options
+    specified in graphOpts.  The default is false.
+
+multimailhook.refchangeShowLog
+    If this option is set to true, then summary emails about reference
+    changes will include a detailed log of the added commits in
+    addition to the one line summary.  The log is generated by running
+    ``git log`` with the options specified in multimailhook.logOpts.
+    Default is false.
+
+multimailhook.mailer
+    This option changes the way emails are sent.  Accepted values are:
+
+    * **sendmail (the default)**: use the command ``/usr/sbin/sendmail`` or
+      ``/usr/lib/sendmail`` (or sendmailCommand, if configured).  This
+      mode can be further customized via the following options:
+
+      multimailhook.sendmailCommand
+          The command used by mailer ``sendmail`` to send emails.  Shell
+          quoting is allowed in the value of this setting, but remember that
+          Git requires double-quotes to be escaped; e.g.::
+
+              git config multimailhook.sendmailcommand '/usr/sbin/sendmail -oi -t -F \"Git Repo\"'
+
+          Default is '/usr/sbin/sendmail -oi -t' or
+          '/usr/lib/sendmail -oi -t' (depending on which file is
+          present and executable).
+
+      multimailhook.envelopeSender
+          If set then pass this value to sendmail via the -f option to set
+          the envelope sender address.
+
+    * **smtp**: use Python's smtplib.  This is useful when the sendmail
+      command is not available on the system.  This mode can be
+      further customized via the following options:
+
+      multimailhook.smtpServer
+          The name of the SMTP server to connect to.  The value can
+          also include a colon and a port number; e.g.,
+          ``mail.example.com:25``.  Default is 'localhost' using port 25.
+
+      multimailhook.smtpUser, multimailhook.smtpPass
+          Server username and password. Required if smtpEncryption is 'ssl'.
+          Note that the username and password currently need to be
+          set cleartext in the configuration file, which is not
+          recommended. If you need to use this option, be sure your
+          configuration file is read-only.
+
+      multimailhook.envelopeSender
+        The sender address to be passed to the SMTP server.  If
+        unset, then the value of multimailhook.from is used.
+
+      multimailhook.smtpServerTimeout
+        Timeout in seconds. Default is 10.
+
+      multimailhook.smtpEncryption
+        Set the security type. Allowed values: ``none``, ``ssl``, ``tls`` (starttls).
+        Default is ``none``.
+
+      multimailhook.smtpCACerts
+        Set the path to a list of trusted CA certificate to verify the
+        server certificate, only supported when ``smtpEncryption`` is
+        ``tls``. If unset or empty, the server certificate is not
+        verified. If it targets a file containing a list of trusted CA
+        certificates (PEM format) these CAs will be used to verify the
+        server certificate. For debian, you can set
+        ``/etc/ssl/certs/ca-certificates.crt`` for using the system
+        trusted CAs. For self-signed server, you can add your server
+        certificate to the system store::
+
+            cd /usr/local/share/ca-certificates/
+            openssl s_client -starttls smtp \
+                   -connect mail.example.net:587 -showcerts \
+                   </dev/null 2>/dev/null \
+                 | openssl x509 -outform PEM >mail.example.net.crt
+            update-ca-certificates
+
+        and used the updated ``/etc/ssl/certs/ca-certificates.crt``. Or
+        directly use your ``/path/to/mail.example.net.crt``. Default is
+        unset.
+
+      multimailhook.smtpServerDebugLevel
+        Integer number. Set to greater than 0 to activate debugging.
+
+multimailhook.from, multimailhook.fromCommit, multimailhook.fromRefchange
+    If set, use this value in the From: field of generated emails.
+    ``fromCommit`` is used for commit emails, ``fromRefchange`` is
+    used for refchange emails, and ``from`` is used as fall-back in
+    all cases.
+
+    The value for these variables can be either:
+
+    - An email address, which will be used directly.
+
+    - The value ``pusher``, in which case the pusher's address (if
+      available) will be used.
+
+    - The value ``author`` (meaningful only for ``fromCommit``), in which
+      case the commit author's address will be used.
+
+    If config values are unset, the value of the From: header is
+    determined as follows:
+
+    1. (gitolite environment only)
+       1.a) If ``multimailhook.MailaddressMap`` is set, and is a path
+       to an existing file (if relative, it is considered relative to
+       the place where ``gitolite.conf`` is located), then this file
+       should contain lines like::
+
+           username Firstname Lastname <email@example.com>
+
+       git-multimail will then look for a line where ``$GL_USER``
+       matches the ``username`` part, and use the rest of the line for
+       the ``From:`` header.
+
+       1.b) Parse gitolite.conf, looking for a block of comments that
+       looks like this::
+
+           # BEGIN USER EMAILS
+           # username Firstname Lastname <email@example.com>
+           # END USER EMAILS
+
+       If that block exists, and there is a line between the BEGIN
+       USER EMAILS and END USER EMAILS lines where the first field
+       matches the gitolite username ($GL_USER), use the rest of the
+       line for the From: header.
+
+    2. If the user.email configuration setting is set, use its value
+       (and the value of user.name, if set).
+
+    3. Use the value of multimailhook.envelopeSender.
+
+multimailhook.MailaddressMap
+    (gitolite environment only)
+    File to look for a ``From:`` address based on the user doing the
+    push. Defaults to unset. See ``multimailhook.from`` for details.
+
+multimailhook.administrator
+    The name and/or email address of the administrator of the Git
+    repository; used in FOOTER_TEMPLATE.  Default is
+    multimailhook.envelopesender if it is set; otherwise a generic
+    string is used.
+
+multimailhook.emailPrefix
+    All emails have this string prepended to their subjects, to aid
+    email filtering (though filtering based on the X-Git-* email
+    headers is probably more robust).  Default is the short name of
+    the repository in square brackets; e.g., ``[myrepo]``.  Set this
+    value to the empty string to suppress the email prefix. You may
+    use the placeholder ``%(repo_shortname)s`` for the short name of
+    the repository.
+
+multimailhook.emailMaxLines
+    The maximum number of lines that should be included in the body of
+    a generated email.  If not specified, there is no limit.  Lines
+    beyond the limit are suppressed and counted, and a final line is
+    added indicating the number of suppressed lines.
+
+multimailhook.emailMaxLineLength
+    The maximum length of a line in the email body.  Lines longer than
+    this limit are truncated to this length with a trailing ``[...]``
+    added to indicate the missing text.  The default is 500, because
+    (a) diffs with longer lines are probably from binary files, for
+    which a diff is useless, and (b) even if a text file has such long
+    lines, the diffs are probably unreadable anyway.  To disable line
+    truncation, set this option to 0.
+
+multimailhook.subjectMaxLength
+    The maximum length of the subject line (i.e. the ``oneline`` field
+    in templates, not including the prefix). Lines longer than this
+    limit are truncated to this length with a trailing ``[...]`` added
+    to indicate the missing text. This option The default is to use
+    ``multimailhook.emailMaxLineLength``. This option avoids sending
+    emails with overly long subject lines, but should not be needed if
+    the commit messages follow the Git convention (one short subject
+    line, then a blank line, then the message body). To disable line
+    truncation, set this option to 0.
+
+multimailhook.maxCommitEmails
+    The maximum number of commit emails to send for a given change.
+    When the number of patches is larger that this value, only the
+    summary refchange email is sent.  This can avoid accidental
+    mailbombing, for example on an initial push.  To disable commit
+    emails limit, set this option to 0.  The default is 500.
+
+multimailhook.excludeMergeRevisions
+    When sending out revision emails, do not consider merge commits (the
+    functional equivalent of `rev-list --no-merges`).
+    The default is `false` (send merge commit emails).
+
+multimailhook.emailStrictUTF8
+    If this boolean option is set to `true`, then the main part of the
+    email body is forced to be valid UTF-8.  Any characters that are
+    not valid UTF-8 are converted to the Unicode replacement
+    character, U+FFFD.  The default is `true`.
+
+    This option is ineffective with Python 3, where non-UTF-8
+    characters are unconditionally replaced.
+
+multimailhook.diffOpts
+    Options passed to ``git diff-tree`` when generating the summary
+    information for ReferenceChange emails.  Default is ``--stat
+    --summary --find-copies-harder``.  Add -p to those options to
+    include a unified diff of changes in addition to the usual summary
+    output.  Shell quoting is allowed; see ``multimailhook.logOpts`` for
+    details.
+
+multimailhook.graphOpts
+    Options passed to ``git log --graph`` when generating graphs for the
+    reference change summary emails (used only if refchangeShowGraph
+    is true).  The default is '--oneline --decorate'.
+
+    Shell quoting is allowed; see logOpts for details.
+
+multimailhook.logOpts
+    Options passed to ``git log`` to generate additional info for
+    reference change emails (used only if refchangeShowLog is set).
+    For example, adding -p will show each commit's complete diff.  The
+    default is empty.
+
+    Shell quoting is allowed; for example, a log format that contains
+    spaces can be specified using something like::
+
+      git config multimailhook.logopts '--pretty=format:"%h %aN <%aE>%n%s%n%n%b%n"'
+
+    If you want to set this by editing your configuration file
+    directly, remember that Git requires double-quotes to be escaped
+    (see git-config(1) for more information)::
+
+      [multimailhook]
+              logopts = --pretty=format:\"%h %aN <%aE>%n%s%n%n%b%n\"
+
+multimailhook.commitLogOpts
+    Options passed to ``git log`` to generate additional info for
+    revision change emails.  For example, adding --ignore-all-spaces
+    will suppress whitespace changes.  The default options are ``-C
+    --stat -p --cc``.  Shell quoting is allowed; see
+    multimailhook.logOpts for details.
+
+multimailhook.dateSubstitute
+    String to use as a substitute for ``Date:`` in the output of ``git
+    log`` while formatting commit messages. This is useful to avoid
+    emitting a line that can be interpreted by mailers as the start of
+    a cited message (Zimbra webmail in particular). Defaults to
+    ``CommitDate:``. Set to an empty string or ``none`` to deactivate
+    the behavior.
+
+multimailhook.emailDomain
+    Domain name appended to the username of the person doing the push
+    to convert it into an email address
+    (via ``"%s@%s" % (username, emaildomain)``). More complicated
+    schemes can be implemented by overriding Environment and
+    overriding its get_pusher_email() method.
+
+multimailhook.replyTo, multimailhook.replyToCommit, multimailhook.replyToRefchange
+    Addresses to use in the Reply-To: field for commit emails
+    (replyToCommit) and refchange emails (replyToRefchange).
+    multimailhook.replyTo is used as default when replyToCommit or
+    replyToRefchange is not set. The shortcuts ``pusher`` and
+    ``author`` are allowed with the same semantics as for
+    ``multimailhook.from``. In addition, the value ``none`` can be
+    used to omit the ``Reply-To:`` field.
+
+    The default is ``pusher`` for refchange emails, and ``author`` for
+    commit emails.
+
+multimailhook.quiet
+    Do not output the list of email recipients from the hook
+
+multimailhook.stdout
+    For debugging, send emails to stdout rather than to the
+    mailer.  Equivalent to the --stdout command line option
+
+multimailhook.scanCommitForCc
+    If this option is set to true, than recipients from lines in commit body
+    that starts with ``CC:`` will be added to CC list.
+    Default: false
+
+multimailhook.combineWhenSingleCommit
+    If this option is set to true and a single new commit is pushed to
+    a branch, combine the summary and commit email messages into a
+    single email.
+    Default: true
+
+multimailhook.refFilterInclusionRegex, multimailhook.refFilterExclusionRegex, multimailhook.refFilterDoSendRegex, multimailhook.refFilterDontSendRegex
+    **Warning:** these options are experimental. They should work, but
+    the user-interface is not stable yet (in particular, the option
+    names may change). If you want to participate in stabilizing the
+    feature, please contact the maintainers and/or send pull-requests.
+    If you are happy with the current shape of the feature, please
+    report it too.
+
+    Regular expressions that can be used to limit refs for which email
+    updates will be sent.  It is an error to specify both an inclusion
+    and an exclusion regex.  If a ``refFilterInclusionRegex`` is
+    specified, emails will only be sent for refs which match this
+    regex.  If a ``refFilterExclusionRegex`` regex is specified,
+    emails will be sent for all refs except those that match this
+    regex (or that match a predefined regex specific to the
+    environment, such as "^refs/notes" for most environments and
+    "^refs/notes|^refs/changes" for the gerrit environment).
+
+    The expressions are matched against the complete refname, and is
+    considered to match if any substring matches. For example, to
+    filter-out all tags, set ``refFilterExclusionRegex`` to
+    ``^refs/tags/`` (note the leading ``^`` but no trailing ``$``). If
+    you set ``refFilterExclusionRegex`` to ``master``, then any ref
+    containing ``master`` will be excluded (the ``master`` branch, but
+    also ``refs/tags/master`` or ``refs/heads/foo-master-bar``).
+
+    ``refFilterDoSendRegex`` and ``refFilterDontSendRegex`` are
+    analogous to ``refFilterInclusionRegex`` and
+    ``refFilterExclusionRegex`` with one difference: with
+    ``refFilterDoSendRegex`` and ``refFilterDontSendRegex``, commits
+    introduced by one excluded ref will not be considered as new when
+    they reach an included ref. Typically, if you add a branch ``foo``
+    to  ``refFilterDontSendRegex``, push commits to this branch, and
+    later merge branch ``foo`` into ``master``, then the notification
+    email for ``master`` will contain a commit email only for the
+    merge commit. If you include ``foo`` in
+    ``refFilterExclusionRegex``, then at the time of merge, you will
+    receive one commit email per commit in the branch.
+
+    These variables can be multi-valued, like::
+
+      [multimailhook]
+              refFilterExclusionRegex = ^refs/tags/
+              refFilterExclusionRegex = ^refs/heads/master$
+
+    You can also provide a whitespace-separated list like::
+
+      [multimailhook]
+              refFilterExclusionRegex = ^refs/tags/ ^refs/heads/master$
+
+    Both examples exclude tags and the master branch, and are
+    equivalent to::
+
+      [multimailhook]
+              refFilterExclusionRegex = ^refs/tags/|^refs/heads/master$
+
+    ``refFilterInclusionRegex`` and ``refFilterExclusionRegex`` are
+    strictly stronger than ``refFilterDoSendRegex`` and
+    ``refFilterDontSendRegex``. In other words, adding a ref to a
+    DoSend/DontSend regex has no effect if it is already excluded by a
+    Exclusion/Inclusion regex.
+
+multimailhook.logFile, multimailhook.errorLogFile, multimailhook.debugLogFile
+
+    When set, these variable designate path to files where
+    git-multimail will log some messages. Normal messages and error
+    messages are sent to ``logFile``, and error messages are also sent
+    to ``errorLogFile``. Debug messages and all other messages are
+    sent to ``debugLogFile``. The recommended way is to set only one
+    of these variables, but it is also possible to set several of them
+    (part of the information is then duplicated in several log files,
+    for example errors are duplicated to all log files).
+
+    Relative path are relative to the Git repository where the push is
+    done.
+
+multimailhook.verbose
+
+    Verbosity level of git-multimail on its standard output. By
+    default, show only error and info messages. If set to true, show
+    also debug messages.
+
+Email filtering aids
+--------------------
+
+All emails include extra headers to enable fine tuned filtering and
+give information for debugging.  All emails include the headers
+``X-Git-Host``, ``X-Git-Repo``, ``X-Git-Refname``, and ``X-Git-Reftype``.
+ReferenceChange emails also include headers ``X-Git-Oldrev`` and ``X-Git-Newrev``;
+Revision emails also include header ``X-Git-Rev``.
+
+
+Customizing email contents
+--------------------------
+
+git-multimail mostly generates emails by expanding templates.  The
+templates can be customized.  To avoid the need to edit
+``git_multimail.py`` directly, the preferred way to change the templates
+is to write a separate Python script that imports ``git_multimail.py`` as
+a module, then replaces the templates in place.  See the provided
+post-receive script for an example of how this is done.
+
+
+Customizing git-multimail for your environment
+----------------------------------------------
+
+git-multimail is mostly customized via an "environment" that describes
+the local environment in which Git is running.  Two types of
+environment are built in:
+
+GenericEnvironment
+    a stand-alone Git repository.
+
+GitoliteEnvironment
+    a Git repository that is managed by gitolite_.  For such
+    repositories, the identity of the pusher is read from
+    environment variable $GL_USER, the name of the repository is read
+    from $GL_REPO (if it is not overridden by multimailhook.reponame),
+    and the From: header value is optionally read from gitolite.conf
+    (see multimailhook.from).
+
+By default, git-multimail assumes GitoliteEnvironment if $GL_USER and
+$GL_REPO are set, and otherwise assumes GenericEnvironment.
+Alternatively, you can choose one of these two environments explicitly
+by setting a ``multimailhook.environment`` config setting (which can
+have the value `generic` or `gitolite`) or by passing an --environment
+option to the script.
+
+If you need to customize the script in ways that are not supported by
+the existing environments, you can define your own environment class
+class using arbitrary Python code.  To do so, you need to import
+``git_multimail.py`` as a Python module, as demonstrated by the example
+post-receive script.  Then implement your environment class; it should
+usually inherit from one of the existing Environment classes and
+possibly one or more of the EnvironmentMixin classes.  Then set the
+``environment`` variable to an instance of your own environment class
+and pass it to ``run_as_post_receive_hook()``.
+
+The standard environment classes, GenericEnvironment and
+GitoliteEnvironment, are in fact themselves put together out of a
+number of mixin classes, each of which handles one aspect of the
+customization.  For the finest control over your configuration, you
+can specify exactly which mixin classes your own environment class
+should inherit from, and override individual methods (or even add your
+own mixin classes) to implement entirely new behaviors.  If you
+implement any mixins that might be useful to other people, please
+consider sharing them with the community!
+
+
+Getting involved
+----------------
+
+Please, read `<CONTRIBUTING.rst>`__ for instructions on how to
+contribute to git-multimail.
+
+
+Footnotes
+---------
+
+.. [1] Because of the way information is passed to update hooks, the
+       script's method of determining whether a commit has already
+       been seen does not work when it is used as an ``update`` script.
+       In particular, no notification email will be generated for a
+       new commit that is added to multiple references in the same
+       push. A workaround is to use --force-send to force sending the
+       emails.
+
+.. _gitolite: https://github.com/sitaramc/gitolite