docker-offlineimap/offlineimap.sgml

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  <!ENTITY OfflineIMAP "<application>OfflineIMAP</application>">
]>
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<reference>
  <title>OfflineIMAP Manual</title>

  <refentry>
    <refentryinfo>
      <address><email>jgoerzen@complete.org</email></address>
      <author><firstname>John</firstname><surname>Goerzen</surname></author>
    </refentryinfo>

    <refmeta>
      <refentrytitle>offlineimap</refentrytitle>
      <manvolnum>1</manvolnum>
      <refmiscinfo>John Goerzen</refmiscinfo>
    </refmeta>

    <refnamediv>
      <refname>OfflineIMAP</refname>
      <refpurpose>Powerful IMAP/Maildir synchronization
	and reader support</refpurpose>
    </refnamediv>

    <refsynopsisdiv>
      <cmdsynopsis>
	<command>offlineimap</command>
	<arg>-1</arg>
	<arg>-P <replaceable>profiledir</replaceable></arg>
	<arg>-a <replaceable>accountlist</replaceable></arg>
	<arg>-c <replaceable>configfile</replaceable></arg>
	<arg>-d <replaceable>debugtype[,...]</replaceable></arg>
	<arg>-l <replaceable>filename</replaceable></arg>
	<arg>-o</arg>
	<arg>-u <replaceable>interface</replaceable></arg>
      </cmdsynopsis>
      <cmdsynopsis>
	<command>offlineimap</command>
	<group choice="plain"><arg>-h</arg><arg>--help</arg></group>
      </cmdsynopsis>
    </refsynopsisdiv>

    <refsect1>
      <title>Description</title>

      <para>&OfflineIMAP; is  a  tool  to  simplify  your  e-mail
	reading.  With &OfflineIMAP;, you can read the same mailbox
	from multiple computers.  You get a current copy of your
	messages on each computer, and changes you make one place will be
	visible on all other systems.  For instance, you can delete a message
	on your home computer, and it will appear deleted on your work
	computer as well.  &OfflineIMAP; is also useful if you want to
	use a mail reader that does not have IMAP support, has poor IMAP
	support, or does not provide disconnected operation.
      </para>

      <para>&OfflineIMAP; is <emphasis>FAST</emphasis>; it synchronizes
        my two accounts with over 50 folders in 3 seconds.  Other
        similar tools might take over a minute, and achieve a
        less-reliable result.  Some mail readers can take over 10
        minutes to do the same thing, and some don't even support it
        at all.  Unlike other mail tools, &OfflineIMAP; features a
        multi-threaded synchronization algorithm that can dramatically
        speed up performance in many situations by synchronizing
        several different things simultaneously.
      </para>

      <para>&OfflineIMAP; is <emphasis>FLEXIBLE</emphasis>; you can
        customize which folders are synced via regular expressions,
        lists, or Python expressions; a versatile and comprehensive
        configuration file is used to control behavior; two user
        interfaces are built-in; fine-tuning of synchronization
        performance is possible; internal or external automation is
        supported; SSL and PREAUTH tunnels are both supported; offline
        (or "unplugged") reading is supported; and esoteric IMAP
        features are supported to ensure compatibility with the widest
        variety of IMAP servers.
      </para>

      <para>&OfflineIMAP; is <emphasis>SAFE</emphasis>; it uses an
        algorithm designed to prevent mail loss at all costs.  Because
        of the design of this algorithm, even programming errors
        should not result in loss of mail.  I am so confident in the
        algorithm that I use my own personal and work accounts for
        testing of &OfflineIMAP; pre-release, development, and beta
	releases.  Of course, legally speaking, &OfflineIMAP; comes
        with no warranty, so I am not responsible if this turns out
        to be wrong.
      </para>

      <refsect2>
        <title>Method of Operation</title>
       
        <para>&OfflineIMAP; traditionally 
	  operates by maintaining a hierarchy of
	  mail folders in Maildir format locally.  Your own mail
	  reader will read mail from this tree, and need never know
	  that the mail comes from IMAP.  &OfflineIMAP; will detect
	  changes to the mail folders on your IMAP server and your own
	  computer and bi-directionally synchronize them, copying,
	  marking, and deleting messages as necessary.
        </para>
	<para>
	  With &OfflineIMAP; 4.0, a powerful new ability has been
	  introduced -- the program can now synchronize two IMAP
	  servers with each other, with no need to have a Maildir
	  layer in-between.  Many people use this if they use a mail
	  reader on their local machine that does not support
	  Maildirs.  People may install an IMAP server on their local
	  machine, and point both &OfflineIMAP; and their mail reader
	  of choice at it.  This is often preferable to the mail
	  reader's own IMAP support since &OfflineIMAP; supports many
	  features (offline reading, for one) that most IMAP-aware
	  readers don't.  However, this feature is not as time-tested
	  as traditional syncing, so my advice is to stick with normal
	  methods of operation for the time being.
	</para>
      </refsect2>
    </refsect1>
    
    <refsect1>
      <title>Quick Start</title>
      <para>If you have already installed &OfflineIMAP; system-wide,
        or your system administrator has done that for you, your task
        for setting up &OfflineIMAP; for the first time is quite
        simple.  You just need to set up your configuration file, make
        your folder directory, and run it!
      </para>

	<para>You can quickly set up your configuration file.  The distribution
	  includes a file <filename>offlineimap.conf.minimal</filename>
	  (Debian users
        may find this at
          <filename>/usr/share/doc/offlineimap/examples/offlineimap.conf.minimal</filename>) that is a basic example of setting of &OfflineIMAP;.  You can
	  simply copy this file into your home directory and name it
	  <filename>.offlineimaprc</filename> (note the leading period).  A
	  command such as <command>cp offlineimap.conf.minimal ~/.offlineimaprc</command> will do it.  Or, if you prefer, you can just copy this text to
	  <filename>~/.offlineimaprc</filename>:
	</para>

	<PROGRAMLISTING>[general]
accounts = Test

[Account Test]
localrepository = Local
remoterepository = Remote

[Repository Local]
type = Maildir
localfolders = ~/Test

[Repository Remote]
type = IMAP
remotehost = examplehost
remoteuser = jgoerzen
</PROGRAMLISTING>

        <para>Now, edit the <filename>~/.offlineimaprc</filename> file with
	  your favorite editor.  All you have to do is specify a directory
	  for your folders to be in (on the <property>localfolders</property>
	  line), the host name of your IMAP server (on the
	  <property>remotehost</property> line), and your login name on
	  the remote (on the <property>remoteuser</property> line).  That's
	  it!</para>

	<para>To run &OfflineIMAP;, you just have to say
	  <command>offlineimap</command> -- it will fire up, ask you for
	  a login password if necessary, synchronize your folders, and exit.
	  See?  You can just throw away the rest of this finely-crafted,
	  perfectly-honed manual!  Of course, if you want to see how you can
	  make &OfflineIMAP; FIVE TIMES FASTER FOR JUST $19.95 (err, well,
	  $0), you have to read on!
	</para>

    </refsect1>

    <refsect1>
      <title>Installation</title>

      <para>If you are reading this document via the "man" command, it is
	likely
	that you have no installation tasks to perform; your system
	administrator has already installed it.  If you need to install it
	yourself, you have three options: a system-wide installation with
	Debian, system-wide installation with other systems, and a single-user
	installation.  You can download the latest version of &OfflineIMAP; from
	<ulink url="http://software.complete.org/offlineimap/">the &OfflineIMAP;
	website</ulink>.
      </para>

      <refsect2>
	<title>Prerequisites</title>

	<para>In order to use &OfflineIMAP;, you need to have these conditions
	  satisfied:
	</para>

	<itemizedlist>
	  <listitem>
	    <para>Your mail server must support IMAP.  Most Internet Service
	      Providers
	      and corporate networks do, and most operating systems
	      have an IMAP
	      implementation readily available.
	    </para>
	  </listitem>
	  <listitem>
	    <para>
	      You must have Python version 2.2.1 or above installed.
	      If you are
	      running on Debian GNU/Linux, this requirement will automatically be
	      taken care of for you.  If you do not have Python already, check with
	      your system administrator or operating system vendor; or, download it from
	      <ulink url="http://www.python.org/">the Python website</ulink>.
		If you intend to use the SSL interface, your
		Python must have been built with SSL support.
	    </para>
	  </listitem>
	  <listitem>
	    <para>
	      Have a mail reader that supports the Maildir mailbox
	      format.  Most modern mail readers have this support
	      built-in, so you can choose from a wide variety of mail
	      servers.  This format is also known as the "qmail"
	      format, so any mail reader compatible with it will work
	      with &OfflineIMAP;.  If you do not have a mail reader
	      that supports Maildir, you can often install a local
	      IMAP server and point both &OfflineIMAP; and your mail
	      reader at it.
	    </para>
	</itemizedlist>
      </refsect2>

      <refsect2>
	<title>System-Wide Installation, Debian</title>
	<para>
	  If you are tracking Debian unstable, you may install
	  &OfflineIMAP; by simply running the following command as root:
	</para>
	<para>
	  <command>apt-get install offlineimap</command>
	</para>
	<para>
	  If you are not tracking Debian unstable, download the Debian .deb
	  package from the <ulink url="http://software.complete.org/offlineimap/">&OfflineIMAP; website</ulink>
	  and then run <command>dpkg -i</command> to install the downloaded
	  package.  Then, skip to <xref linkend="configuration" endterm="configuration-title"> below.  You will type <command>offlineimap</command> to
	  invoke the program.
	</para>
      </refsect2>

      <refsect2>
	<title>System-Wide Installation, Other</title>
	<para>
	  Download the tar.gz version of the package from the
	  <ulink url="http://software.complete.org/offlineimap/">website</ulink>.
	  Then run
	  these commands, making sure that you are the "root" user first:
	</para>

	<ProgramListing>tar -zxvf offlineimap_x.y.z.tar.gz
cd offlineimap-x.y.z
python2.2 setup.py install</ProgramListing>
	<para>On some systems, you will need to use
	  <command>python</command> instead of <command>python2.2</command>.
	  Next, proceed to <xref linkend="configuration" endterm="configuration-title"> below.  You will type <command>offlineimap</command> to
	  invoke the program.
	</para>
      </refsect2>

      <refsect2>
	<title>Single-Account Installation</title>
	<para>
	  Download the tar.gz version of the package from the
	  <ulink url="http://software.complete.org/offlineimap/">website</ulink>.
	  Then run these commands:
	</para>

	<ProgramListing>tar -zxvf offlineimap_x.y.z.tar.gz
cd offlineimap-x.y.z</ProgramListing>

	<para>When you want to run &OfflineIMAP;, you will issue the
	  <command>cd</command> command as above and then type
	  <command>./offlineimap.py</command>; there is no installation
	  step necessary.
	</para>
      </refsect2>
    </refsect1>

    <refsect1 id="configuration">
      <title id="configuration-title">Configuration</title>
      <para>
	&OfflineIMAP; is regulated by a configuration file that is normally 
	stored in <filename>~/.offlineimaprc</filename>.  &OfflineIMAP;
	ships with a file named <filename>offlineimap.conf</filename>
	that you should copy to that location and then edit.  This file is
	vital to proper operation of the system; it sets everything you need
	to run &OfflineIMAP;.  Full documentation for the configuration file
	is included within the sample file.
      </para>
      <para>
	&OfflineIMAP; also ships a file named
	<filename>offlineimap.conf.minimal</filename> that you can also try.
	  It's useful if you want to get started with
	  the most basic feature set, and you can read about other features
	  later with <filename>offlineimap.conf</filename>.
      </para>
    </refsect1>

    <refsect1>
      <title>Options</title>
      <para>
	Most configuration is done via the configuration file.  Nevertheless,
	there are a few command-line options that you may set for
	&OfflineIMAP;.
      </para>

      <variablelist>
        <varlistentry><term>-1</term>
          <listitem><para>Disable most multithreading operations and use
	    solely a single-connection
	    sync.  This effectively sets the
	      <property>maxsyncaccounts</property>
	    and all <property>maxconnections</property> configuration file
	    variables to 1.
	  </para></listitem>
	</varlistentry>
	<varlistentry><term>-P <replaceable>profiledir</replaceable></term>
	  <listitem><para>Sets &OfflineIMAP; into profile mode.  The program
	    will create <replaceable>profiledir</replaceable>
	    (it must not already exist).  As it runs, Python profiling 
	    information
	    about each thread is logged into profiledir.  Please note: This option
	    is present for debugging and optimization only, and should NOT be used
	    unless you have a specific reason to do so.  It will significantly
	    slow program performance, may reduce reliability, and can generate
	    huge amounts of data.  You must use the <option>-1</option> option when
	    you use <option>-P</option>.
	  </para></listitem>
	</varlistentry>
	<varlistentry><term>-a <replaceable>accountlist</replaceable></term>
	  <listitem><para>Overrides the <property>accounts</property> option
	    in the <property>general</property> section of the configuration
	    file.  You might use this to exclude certain accounts, or to sync
	    some accounts that you normally prefer not to.  Separate the
	    accounts by commas, and use no embedded spaces.
	  </para></listitem>
	</varlistentry>
	<varlistentry><term>-c <replaceable>configfile</replaceable></term>
	  <listitem><para>Specifies a configuration file to use in lieu of
	    the default, <filename>~/.offlineimaprc</filename>.
	  </para></listitem>
	</varlistentry>
	<varlistentry><term>-d <replaceable>debugtype[,...]</replaceable></term>
	  <listitem><para>Enables debugging for OfflineIMAP.  This is useful if
	    you are trying to track down a malfunction or figure out what is going
	    on under the hood.  I suggest that you use this with
	    <option>-1</option> to make the results more sensible.</para>

	    <para><option>-d</option> requires one or more debugtypes,
	      separated by commas.  These define what exactly will be
	      debugged, and include three options: <property>imap</property>,
	      <property>maildir</property>, and <property>thread</property>.
	      The <property>imap</property>
	      option will enable IMAP protocol stream and parsing debugging.  Note
	      that the output may contain passwords, so take care to remove that
	      from the debugging output before sending it to anyone else.  The
	      <property>maildir</property> option will enable debugging for
	      certain Maildir operations.  And <property>thread</property>
	      will debug the threading model.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry><term>-l
	  <replaceable>filename</replaceable></term>
	    <listitem><para>
	      Enables logging to filename.  This will log everything
	      that goes to the screen to the specified file.
	      Additionally, if any debugging is specified with -d,
	      then debug messages will not go to the screen, but
	      instead to the logfile only.</para>
	  </listitem>
	</varlistentry>
	  <varlistentry><term>-o</term>
	    <listitem><para>Run only once, ignoring all
	      <property>autorefresh</property> settings in the configuration
	      file.</para>
	    </listitem>
	  </varlistentry>
	  <varlistentry><term>-h</term> <term>--help</term>
	    <listitem><para>Show summary of options.</para></listitem>
	  </varlistentry>
	  <varlistentry><term>-u <replaceable>interface</replaceable></term>
	    <listitem><para>Specifies an alternative user interface module
	      to use.  This overrides the default specified in the
	      configuration file.  The pre-defined options are listed in
	      the User Interfaces section.</para>
	    </listitem>
	  </varlistentry>
      </variablelist>
    </refsect1>
    <refsect1>
      <title>User Interfaces</title>
      <para>&OfflineIMAP; has a pluggable user interface system that lets you choose how the
	program communicates information to you.  There are two graphical
	interfaces, two terminal interfaces, and two noninteractive interfaces
	suitable for scripting or logging purposes.  The
	<property>ui</property> option in the configuration file specifies
	user interface preferences.  The <option>-u</option> command-line
	option can override the configuration file setting.  The available
	values for the configuration file or command-line are described
	in this section.</para>

      <refsect2>
	<title>Curses.Blinkenlights</title>
	<para>
                Curses.Blinkenlights is an interface designed to be sleek, fun to watch, and
	  informative of the overall picture of what &OfflineIMAP;
	  is doing.  I consider it to be the best general-purpose interface in
	  &OfflineIMAP;.
	</para>
	<para>
	  Curses.Blinkenlights contains a row of
          "LEDs" with command buttons and a log.
	  The  log shows more
	  detail about what is happening and is color-coded to match the color
	  of the lights.
	</para>
	<para>
	  Each light in the Blinkenlights interface represents a thread
	  of execution -- that is, a particular task that &OfflineIMAP;
	  is performing right now.  The colors indicate what task
	  the particular thread is performing, and are as follows:
	</para>
	<variablelist>
	  <varlistentry>
	    <term>Black</term>
	    <listitem><para>indicates that this light's thread has terminated; it will light up
	      again later when new threads start up.  So, black indicates no
	      activity.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Red (Meaning 1)</term>
	    <listitem><para>is the color of the main program's thread, which basically does
	      nothing but monitor the others.  It might remind you of HAL 9000 in
	      <citation>2001</citation>.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Gray</term>
	    <listitem><para>indicates that the thread is establishing a new connection to the IMAP
	      server.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Purple</term>
	    <listitem><para>is the color of an account synchronization thread that is monitoring
	      the progress of the folders in that account (not generating any I/O).
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Cyan</term>
	    <listitem><para>indicates that the thread is syncing a folder.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Green</term>
	    <listitem><para>means that a folder's message list is being loaded.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Blue</term>
	    <listitem><para>is the color of a message synchronization controller thread.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Orange</term>
	    <listitem><para>indicates that an actual message is being copied.
	      (We use fuchsia for fake messages.)
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Red (meaning 2)</term>
	    <listitem><para>indicates that a message is being deleted.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Yellow / bright orange</term>
	    <listitem><para>indicates that message flags are being added.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Pink / bright red</term>
	    <listitem><para>indicates that message flags are being removed.
	    </para></listitem>
	  </varlistentry>
	  <varlistentry>
	    <term>Red / Black Flashing</term>
	    <listitem><para>corresponds to the countdown timer that runs between
	      synchronizations.
	    </para></listitem>
	  </varlistentry>
	</variablelist>
	<para>The name of this interfaces derives from a bit of computer
	  history.  Eric Raymond's <citation>Jargon File</citation> defines
	  <firstterm>blinkenlights</firstterm>, in part, as:
	</para>
	<blockquote>
	  <para>Front-panel diagnostic
	    lights on a computer, esp. a dinosaur. Now that dinosaurs are rare,
	    this term usually refers to status lights on a modem, network hub, or
	    the like.
	  </para>
	  <para>
	    This term derives from the last word of the famous blackletter-Gothic
	    sign in mangled pseudo-German that once graced about half the computer
	    rooms in the English-speaking world. One version ran in its entirety as
	    follows:
	  </para>
	  <para>
	    <emphasis>ACHTUNG!  ALLES LOOKENSPEEPERS!</emphasis>
	  </para>
	  <para>
	    Das computermachine ist nicht fuer gefingerpoken und mittengrabben.
	    Ist easy schnappen der springenwerk, blowenfusen und poppencorken
	    mit spitzensparken.  Ist nicht fuer gewerken bei das dumpkopfen.
	    Das rubbernecken sichtseeren keepen das cotten-pickenen hans in das
	    pockets muss; relaxen und watchen das blinkenlichten.
	  </para>
	</blockquote>
      </refsect2>

      <refsect2>
	<title>TTY.TTYUI</title>
	<para>
	  TTY.TTYUI interface is for people running in basic, non-color terminals.  It
	  prints out basic status messages and is generally friendly to use on a console
	  or xterm.
	</para>
      </refsect2>

      <refsect2>
	<title>Noninteractive.Basic</title>
	<para>
	  Noninteractive.Basic is designed for situations in which &OfflineIMAP;
	  will be run non-attended and the status of its execution will be
	  logged.  You might use it, for instance, to have the system run
	  automatically and
	  e-mail you the results of the synchronization.  This user interface
	  is not capable of reading a password from the keyboard; account
	  passwords must be specified using one of the configuration file options.
	</para>
      </refsect2>

      <refsect2>
	<title>Noninteractive.Quiet</title>
	<para>
	  Noninteractive.Quiet is designed for non-attended running in situations
	  where normal status messages are not desired.  It will output nothing
	  except errors and serious warnings.  Like Noninteractive.Basic,
	  this user interface
	  is not capable of reading a password from the keyboard; account
	  passwords must be specified using one of the configuration file options.
	</para>
      </refsect2>

    </refsect1>

    <refsect1>
      <title>Examples</title>
      <para>Here are some example configurations for various situations.
	Please e-mail any other examples you have that may be useful to
	me.
      </para>

      <refsect2>
	<title>Multiple Accounts with Mutt</title>
	<para>
	  This example shows you how to set up &OfflineIMAP; to
	  synchronize multiple accounts with the mutt mail reader.
	</para>
	<para>
	  Start by creating a directory to hold your folders by running
	  <command>mkdir ~/Mail</command>.  Then, in your
	  <filename>~/.offlineimaprc</filename>, specify:
	</para>
	<programlisting>accounts = Personal, Work</programlisting>
	<para>
	  Make sure that you have both an
	  <property>[Account Personal]</property>
	  and an <property>[Account Work]</property> section.  The
	  local repository for each account must have different
	  <property>localfolder</> path names.
	  Also, make sure
	  to enable <property>[mbnames]</property>.
	</para>
	<para>
	  In each local repository section, write something like this:
	</para>
	<programlisting>localfolders = ~/Mail/Personal</programlisting>
	<para>
	  Finally, add these lines to your <filename>~/.muttrc</filename>:
	</para>
	<programlisting>source ~/path-to-mbnames-muttrc-mailboxes
folder-hook Personal set from="youremail@personal.com"
folder-hook Work set from="youremail@work.com"
set mbox_type=Maildir
set folder=$HOME/Mail
spoolfile=+Personal/INBOX</programlisting>
	<para>
	  That's it!
	</para>
      </refsect2>

      <refsect2>
	<title>UW-IMAPD and References</title>
	<para>Some users with a UW-IMAPD server need to use &OfflineIMAP;'s
	  "reference" feature to get at their mailboxes, specifying a reference
	  of "~/Mail" or "#mh/" depending on the configuration.  The below
	  configuration from (originally from docwhat@gerf.org)
	  shows using a <property>reference</property> of Mail, a <property>nametrans</property>
	  that strips
	  the leading Mail/ off incoming folder names, and a
	  <property>folderfilter</property> that
	  limits the folders synced to just three.
	</para>
	<programlisting>[Account Gerf]
localrepository = GerfLocal
remoterepository = GerfRemote

[Repository GerfLocal]
type = Maildir
localfolders = ~/Mail

[Repository GerfRemote]
type = IMAP
remotehost = gerf.org
ssl = yes
remoteuser = docwhat
reference = Mail
# Trims off the preceeding Mail on all the folder names.
nametrans = lambda foldername: \
            re.sub('^Mail/', '', foldername)
# Yeah, you have to mention the Mail dir, even though it
# would seem intuitive that reference would trim it.
folderfilter = lambda foldername: foldername in [
      'Mail/INBOX',
      'Mail/list/zaurus-general',
      'Mail/list/zaurus-dev',
      ]
maxconnections = 1
holdconnectionopen = no</programlisting>
      </refsect2>

      <refsect2>
	<title>pythonfile Configuration File Option</title>
	<para>You can have &OfflineIMAP;
	  load up a Python file before evaluating the
	  configuration file options that are Python expressions.  This example
	  is based on one supplied by Tommi Virtanen for this feature.
	</para>
	<para>
	  In <filename>~/.offlineimap.rc</filename>, he adds these options:
	</para>
	<programlisting>[general]
pythonfile=~/.offlineimap.py
[Repository foo]
foldersort=mycmp</programlisting>
	<para>
	  Then, the <filename>~/.offlineimap.py</filename> file will
	  contain:
	</para>
	<programlisting>prioritized = ['INBOX', 'personal', 'announce', 'list']

def mycmp(x, y):
   for prefix in prioritized:
       xsw = x.startswith(prefix)
       ysw = y.startswith(prefix)
       if xsw and ysw:
          return cmp(x, y)
       elif xsw:
          return -1
       elif ysw:
          return +1
   return cmp(x, y)

def test_mycmp():
   import os, os.path
   folders=os.listdir(os.path.expanduser('~/data/mail/tv@hq.yok.utu.fi'))
   folders.sort(mycmp)
   print folders</programlisting>
	<para>
	  This code snippet illustrates how the <property>foldersort</property>
	  option can be customized with a Python function from the
	  <property>pythonfile</property> to always synchronize certain
	  folders first.
	</para>
      </refsect2>
    </refsect1>
      
    <refsect1>
      <title>Errors</title>
      <para>
	If you get one of some frequently-encountered or confusing errors,
	please check this section.
      </para>
      
      <refsect2>
	<title>UID validity problem for folder</title>
	<para>IMAP servers use a unique ID (UID) to refer to a specific message.
	  This number is guaranteed to be unique to a particular message
	  <emphasis>forever</emphasis>.
	  No other message in the same folder will ever get the same
	  UID.  UIDs are an integral part of &OfflineIMAP;'s synchronization
	  scheme; they are used to match up messages on your computer to
	  messages on the server.
	</para>

	<para>
	  Sometimes, the UIDs on the server might get reset.  Usually this will
	  happen if you delete and then recreate a folder.  When you create a
	  folder, the server will often start the UID back from 1.  But
	  &OfflineIMAP; might still have the UIDs from the previous folder by the
	  same name stored.  &OfflineIMAP; will detect this condition and skip the
	  folder.  This is GOOD, because it prevents data loss.
	</para>

	<para>
	  You can fix it by removing your local folder and cache data.  For
	  instance, if your folders are under <filename>~/Folders</filename>
	  and the folder with the problem is INBOX, you'd type this:
	</para>

	<programlisting>rm -r ~/Folders/INBOX
rm -r ~/.offlineimap/Account-<replaceable>AccountName</>
rm -r ~/.offlineimap/Repository-<replaceable>RepositoryName</></programlisting>

	<para>
	  (Of course, replace AccountName and RepositoryName 
	  with the names as specified
	  in <filename>~/.offlineimaprc</filename>).
	</para>

	<para>Next time you run &OfflineIMAP;, it will re-download
	  the folder with the
	  new UIDs.  Note that the procedure specified above will lose any local
	  changes made to the folder.
	</para>

	<para>
	  Some IMAP servers are broken and do not support UIDs properly.  If you
	  continue to get this error for all your folders even after performing
	  the above procedure, it is likely that your IMAP server falls into
	  this category.  &OfflineIMAP; is incompatible with such servers.
	  Using &OfflineIMAP; with them will not destroy any mail, but at the same time,
	  it will not actually synchronize it either.  (&OfflineIMAP; will detect
	  this condition and abort prior to synchronization.)
	</para>
	<para>
	  This question comes up frequently on the
	  <ulink
	  url="http://lists.complete.org/offlineimap@complete.org/">&OfflineIMAP;
	  mailing list</ulink>.  You can find a
	  <ulink
	  url="http://lists.complete.org/offlineimap@complete.org/2003/04/msg00012.html.gz">detailed
	  discussion</ulink> of the problem there.
	</para>
      </refsect2>
    </refsect1>
    <refsect1>
      <title>Conforming To</title>
      <itemizedlist>
	<listitem><para>Internet Message Access Protocol version 4rev1 (IMAP 4rev1) as
	  specified in RFC2060 and RFC3501</para></listitem>
	<listitem><para>CRAM-MD5 as specified in RFC2195</para></listitem>
	<listitem><para>Maildir as specified in
	  <ulink url="http://www.qmail.org/qmail-manual-html/man5/maildir.html">the Maildir manpage</ulink> and
	  <ulink url="http://cr.yp.to/proto/maildir.html">the qmail website</ulink>.</para></listitem>
	<listitem><para>Standard Python 2.2.1 as implemented on POSIX-compliant systems.</para></listitem>
      </itemizedlist>
    </refsect1>

    <refsect1>
      <title>Notes</title>
      <refsect2>
	<title>Deleting Local Folders</title>
	<para>&OfflineIMAP; does a two-way synchronization.  That is, if you
	  make a change to the mail on the server, it will be propagated to your
	  local copy, and vise-versa.  Some people might think that it would be
	  wise to just delete all their local mail folders periodically.  If you
	  do this with &OfflineIMAP;, remember to also remove your local status
	  cache (<filename>~/.offlineimap</filename> by default).  Otherwise, &OfflineIMAP; will take
	  this as an intentional deletion of many messages and will interpret
	  your action as requesting them to be deleted from the server as well.
	  (If you don't understand this, don't worry; you probably won't
	  encounter this situation)
	</para>
      </refsect2>

      <refsect2>
	<title>Multiple Instances</title>
	<para>&OfflineIMAP; is not designed to have several instances (for instance, a cron job and an interactive invocation) run over the same
	  mailbox simultaneously.  It will perform a check on startup and
	  abort if another &OfflineIMAP; is already running.  If you need
	  to schedule synchronizations, please use the
	  <property>autorefresh</property> settings rather than cron.
	  Alternatively, you can set a separate <property>metadata</property>
	  directory for each instance.
	</para>
      </refsect2>

      <refsect2>
	<title>Copying Messages Between Folders</title>
	<para>
	  Normally, when you copy a message between folders or add a new message
	  to a folder locally, &OfflineIMAP;
	  will just do the right thing.  However, sometimes this can be tricky
	  -- if your IMAP server does not provide the SEARCH command, or does
	  not return something useful, &OfflineIMAP;
	  cannot determine the new UID of the message.  So, in these rare
	  instances, OfflineIMAP will upload the message to the IMAP server and
	  delete it from your local folder.  Then, on your next sync, the
	  message will be re-downloaded with the proper UID.
	  &OfflineIMAP; makes sure that the message was properly uploaded before deleting it,
	  so there should be no risk of data loss.
	</para>
      </refsect2>


      <refsect2>
	<title>Mailing List</title>
	<para>There is an OfflineIMAP mailing list available.
	  To subscribe, send the text "Subscribe" in the subject of a mail to
	  offlineimap-request@complete.org.  To post, send the message to
	  offlineimap@complete.org.  Archives are available at
	  <ulink url="http://lists.complete.org/offlineimap@complete.org/"></>.
	</para>
      </refsect2>

      <refsect2>
	<title>Bugs</title>
	<para>
          Reports of bugs should be reported online at the
          &OfflineIMAP; homepage.
          Debian users are encouraged to instead use the
	Debian
          bug-tracking system.
	</para>
      </refsect2>
    </refsect1>

    <refsect1 id="upgrading.4.0">
      <title>Upgrading to 4.0</title>
      <para>
	If you are upgrading from a version of &OfflineIMAP; prior to
	3.99.12, you will find that you will get errors when
	&OfflineIMAP; starts up (relating to ConfigParser or
	AccountHashGenerator) and the
	configuration file.  This is because the config file format
	had to change to accommodate new features in 4.0.  Fortunately,
	it's not difficult to adjust it to suit.
      </para>
      <para>
	First thing you need to do is stop any running &OfflineIMAP;
	instance, making sure first that it's synced all your mail.
	Then, modify your
	<filename>~/.offlineimaprc</filename> file.  You'll need to
	split up each account section (make sure that it now starts
	with "Account ") into two Repository sections (one for the
	local side and another for the remote side.)  See the files
	<filename>offlineimap.conf.minimal</filename> and
	<filename>offlineimap.conf</filename> in the distribution if
	you need more assistance.
      </para>
      <para>
	&OfflineIMAP;'s status directory area has also changed.
	Therefore, you should delete everything in ~/.offlineimap as
	well as your local mail folders.
      </para>
      <para>
	When you start up &OfflineIMAP; 4.0, it will re-download all
	your mail from the server and then you can continue using it
	like normal.
      </para>
    </refsect1>
	

    <refsect1>
      <title>Copyright</title>
      <para>OfflineIMAP, and this manual, are Copyright &copy; 2002 - 2006 John Goerzen.</para>

      <para>
	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.
      </para>

      <para>
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.
      </para>

      <para>
	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA</para>

      <para>imaplib.py comes from the Python dev tree and is licensed under
	the GPL-compatible PSF license as stated in the file
	<filename>COPYRIGHT</filename> in the &OfflineIMAP;
         distribution.
      </para>
    </refsect1>

    <refsect1>
      <title>Author</title>
      <para>&OfflineIMAP;, its libraries, documentation, and all included files, except where
	noted, was written by John Goerzen <email>jgoerzen@complete.org</email> and
	copyright is held as stated in the COPYRIGHT section.
      </para>

      <para>
	&OfflineIMAP; may be downloaded, and information found, from its
	<ulink url="http://software.complete.org/offlineimap">homepage</ulink>.
      </para>

    </refsect1>

    <refsect1>
      <title>See Also</title>
      <para><application>mutt</application>(1),
	<application>python</application>(1)
      </para>
    </refsect1>

    <refsect1>
      <title>History</title>
      <para>
	Detailed history may be found in the file ChangeLog in the
	&OfflineIMAP; distribution.  Feature and bug histories may be
	found in the file debian/changelog which, despite its name, is
	not really Debian-specific.  This section provides a large
	overview.
      </para>
      <para>
	Development on &OfflineIMAP; began on June 18, 2002.  Version
	1.0.0 was released three days later on June 21, 2002.  Point
	releases followed, including speed optimizations and some
	compatibility fixes.
      </para>
      <para>Version 2.0.0 was released on July 3, 2002, and
	represented the first time the synchronization became
	multithreaded and, to the best of my knowledge, the first
	multithreaded IMAP syncrhonizing application in existance.
	The last 2.0.x release, 2.0.8, was made on July 9.
      </para>
      <para>
	Version 3.0.0 was released on July 11, 2002, and introduced
	modular user interfaces and the first GUI interface for
	&OfflineIMAP;.  This manual also was introduced with 3.0.0,
	along with many command-line options.  Version 3.1.0 was
	released on July 21, adding the Noninteractive user
	interfaces, profiling support, and several bugfixes.  3.2.0
	was released on July 24, adding support for the Blinkenlights
	GUI interface.  &OfflineIMAP; entered maintenance mode for
	awhile, as it had reached a feature-complete milestone in my
	mind.
      </para>
      <para>
	The 3.99.x branch began in on October 7, 2002, to begin work
	for 4.0.  The Curses.Blinkenlights interface was added in
	3.99.6, and many architectural changes were made.
      </para>
      <para>
	4.0.0 was released on July 18, 2003, including the ability to
            synchronize directly between two IMAP servers, the first
            re-architecting of the configuration file to refine the
            notion of an account, and the new Curses interface.
      </para>
    </refsect1>
  </refentry>
</reference>

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