docker-offlineimap/offlineimap/head/offlineimap.1

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.\" other parameters are allowed: see man(7), man(1)
.TH OFFLINEIMAP 1 "July 12, 2002" "John Goerzen" "OfflineIMAP manual"
.\" Please adjust this date whenever revising the manpage.
.\"
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.SH NAME
OfflineIMAP \- Powerful IMAP/Maildir synchronization and reader support
.SH SYNOPSIS
.B offlineimap
[
.BI \-1
]
[
.BI \-a \ accountlist
]
[
.BI \-c \ configfile
]
.br
[
.BI \-d
]
[
.BI \-o
]
[
.BI \-u " interface"
]

.\".RI [ -c \ foo ]
.\".RI [ options ] " files" ...
.br
.B offlineimap
.B \-h 
|
.B \-\-help
.\".RI [ options ] " files" ...
.SH DESCRIPTION
.B OfflineIMAP
is a tool to simplify your e-mail reading.  With 
.B 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.
.B 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.
.PP
.B OfflineIMAP
is
.I FAST;
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,
.B OfflineIMAP
features a multi-threaded synchronization algorithm that can
dramatically speed up performance in many situations by synchronizing
several different things simultaneously.
.PP
.B OfflineIMAP
is
.I FLEXIBLE;
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.
.PP
.B OfflineIMAP
is
.I SAFE;
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
.B OfflineIMAP
pre-release, development, and beta releases.
.SS "METHOD OF OPERATION"
.B OfflineIMAP
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.
.B 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.
.SH INSTALLATION
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
.UR http://quux.org/devel/offlineimap/
http://quux.org/devel/offlineimap/.
.UE
.SS PREREQUISITES
In order to use OfflineIMAP, you need to have these conditions
satisfied:
.IP \(bu
Your mail server must support IMAP.  Most Internet Service Providers
and corporate networks do, and most operating systems have an IMAP
implementation readily available.
.IP \(bu
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
.UR http://www.python.org/
http://www.python.org/.
.UE
If you intend to use the Tk interface, you must have Tkiner
(python-tk) installed.  If you intend to use the SSL interface, your
Python must have been built with SSL support.
.IP \(bu
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.
.SS DEBIAN SYSTEM-WIDE INSTALLATION
If you are tracking Debian unstable, you may install
.B OfflineIMAP
by simply running the following command as root:
.PP
.B apt-get install offlineimap
.PP
If you are not tracking Debian unstable, download the Debian .deb
package from the OfflineIMAP website
and then run
.B dpkg -i
to install the downloaded package.  Then, go to CONFIGURATION below.
You will type
.B offlineimap
to invoke the program.
.SS OTHER SYSTEM-WIDE INSTALLATION
Download the tar.gz version of the package from the website.  Then run
these commands:
.PP
.B tar -zxvf offlineimap-x.y.z.tar.gz
.br
.B cd offlineimap-x.y.z
.br
.B python2.2 setup.py
.PP
Some systems will need to use
.B python
instead of
.B python2.2.
Next, proceed to configuration.  You will type
.B offlineimap
to invoke the program.
.SS SINGLE-ACCOUNT INSTALLATION
Download the tar.gz version of the package from the website.  Then run
these commands:
.PP
.B tar -zxvf offlineimap-x.y.z.tar.gz
.br
.B cd offlineimap-x.y.z
.PP
When you want to run
.B OfflineIMAP,
you will issue the
.B cd
command as above and then type
.B ./offlineimap;
there is no installation step necessary.
.\"##################################################
.SH CONFIGURATION
.B OfflineIMAP
is regulated by a configuration file that is normally stored in
.I ~/.offlineimaprc.
.B OfflineIMAP
ships with a file named
.I offlineimap.conf
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
.B OfflineIMAP.
Full documentation for the configuration file is included within the
sample file.
.\"##################################################
.\" TeX users may be more comfortable with the \fB<whatever>\fP and
.\" \fI<whatever>\fP escape sequences to invode bold face and italics, 
.\" respectively.
.\"\fBofflineimap\fP is a program that...
.SH OPTIONS
Most configuration is done via the configuration file.  Nevertheless,
there are a few options that you may set for
.B OfflineIMAP.
.TP
.B \-1
Disable all multithreading operations and use solely a single-thread
sync.  This effectively sets the
.B maxsyncaccounts
and all
.B maxconnections
configuration file variables to 1.
.TP
.BI \-a \ accountlist
Overrides the
.B accounts
section in the config file.  Lets you specify a particular account or
set of accounts to sync without having to edit the config file.  You
might use this to exclude certain accounts, or to sync some accounts
that you normally prefer not to.
.TP
.BI \-c \ configfile
Specifies a configuration file to use in lieu of the default,
.I ~/.offlineimaprc.
.TP
.BI \-d
Enables IMAP protocol stream and parsing debugging.  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
.BI \-1
in order to make the results more sensible.  Note that this output
will contain full IMAP protocol in plain text, including passwords, so
take care to remove that from the debugging output before sending it
to anyone else.
.TP
.B \-o
Run only once, ignoring any autorefresh setting in the config file.  
.TP
.B \-h, \-\-help
Show summary of options.
.TP
.BI \-u \ interface
Specifies an alternative user interface module to use.  This overrides
the default specified in the configuration file.  The UI specified
with
.B -u
will be forced to be used, even if its
.B isuable()
method states that it cannot be.  Use this option with care.
.IP
The pre-defined options are
.B Tk.TKUI
(a graphical interface)
and
.B TTY.TTYUI
(a text-mode interface).
.\".TP
.\".B \-v, \-\-version
.\"Show version of program.
.SH EXAMPLES
Here is an example configuration for a particularly complex situation;
more examples will be added later.
.SS MULTIPLE ACCOUNTS WITH MUTT
This example shows you how to set up
.B OfflineIMAP
to synchronize multiple accounts with the mutt mail reader.
.PP
Start by creating a directory to hold your folders:
.br
.B mkdir ~/Mail
.PP
In your
.I ~/.offlineimaprc,
specify this:
.br
.B accounts = Personal, Work
.PP
Make sure that you have both a
.B [Personal]
and a
.B [Work]
section, with different localfolder pathnames and enable
.B [mbnames].
.PP
In each account section, do something like this:
.br
.B localfolders = ~/Mail/Personal
.PP
Add these lines to your
.I ~/.muttrc:
.br
.B source ~/path-to-mbnames-muttrc-mailboxes
.br
.B folder-hook Personal set from="youremail@personal.com"
.br
.B folder-hook Work set from="youremail@work.com"
.br
.B set mbox_type=Maildir
.br
.B set folder=$HOME/Mail
.br
.B set spoolfile=+Personal/INBOX
.PP
That's it!
.SH ERRORS
If you get one of some frequently-encountered or confusing errors,
please check this section.
.SS UID validity problem for folder
IMAP servers use a unique ID (UID) to refer to a specific message.
This number is guaranteed to be unique to a particular message
FOREVER.  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.
.PP
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
.B OfflineIMAP
might still have the UIDs from the previous folder by the
same name stored.
.B OfflineIMAP
will detect this condition and skip the
folder.  This is GOOD, because it prevents data loss.
.PP
You can fix it by removing your local folder and cache data.  For
instance, if your folders are under
.I ~/Folders
and the folder with the
problem is INBOX, you'd type this:
.PP
.B rm -r ~/Folders/INBOX
.br
.B rm ~/.offlineimap/AccountName/INBOX
.PP
(replacing AccountName with the account name as specified in
.I ~/.offlineimaprc)
.PP
Next time you run
.B 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.
.PP
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.
.B OfflineIMAP
is incompatible with such servers.  Using
.B 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)

.SH OTHER FREQUENTLY ASKED QUESTIONS
There are some other FAQs that might not fit into another section of
this document, and they are enumerated here.
.TP
.B What platforms does OfflineIMAP run on?
It should run on most platforms supported by Python, which are quite a
few.
.TP
.B I'm using Mutt.  Other IMAP sync programs require me to use "set maildir_trash=yes".  Do I need to do that with OfflineIMAP?
No.
.B OfflineIMAP
is smart enough to figure out message deletion without this extra
crutch.  You'll get the best results if you don't use this setting, in
fact.
.TP
.B How do I specify the names of my folders?
You do not need to.
.B OfflineIMAP
is smart enough to automatically figure out what folders are present
on the IMAP server and synchronize them.  You can use the
.B folderfilter
and
.B foldertrans
configuration file options to request certain folders and rename them
as they come in if you like.
.TP
.B How can I prevent certain folders from being synced?
Use the
.B folderfilter
option in the configuration file.
.TP
.B How can I add or delete a folder?
.B OfflineIMAP
does not currently provide this feature, but if you create a new
folder on the IMAP server, it will be created locally automatically.
.TP
.B Are there any other warnings that I should be aware of?
Yes; see the NOTES section below.
.TP
.B What is the mailbox name recorder (mbnames) for?
The Mutt mail reader is not capable of automatically determining
the names of your mailboxes.  OfflineIMAP can help it (or many other)
programs out be writing these names out in a format you specify.  See
the example offlineimap.conf file for details.
.TP
.B Can I synchronize multiple accounts with OfflineIMAP?
Sure.  Just name them all in the accounts line in the general
section of the config file, and add a per-account section for each one.
.TP
.B Does OfflineIMAP support POP?
No.  POP is not robust enough to do a completely reliable
multi-machine synchronization like OfflineIMAP can do.  OfflineIMAP
will not support it.
.TP
.B Do you support mailbox formats other than Maildir?
Not at present.  There is no technical reason not to; just no
demand yet.  Maildir is a superior format anyway.
.TP
.B [technical] Why are your Maildir message filenames so huge?
.B OfflineIMAP
has two relevant principles: 1) never modifying your
messages in any way and 2) ensuring 100% reliable synchronizations.
In order to do a reliable sync,
.B OfflineIMAP
must have a way to
uniquely identify each e-mail.  Three pieces of information are
required to do this: your account name, the folder name, and the
message UID.  The account name can be calculated from the path in
which your messages are.  The folder name can usually be as well, BUT
some mail clients move messages between folders by simply moving the
file, leaving the name intact.
.IP
So,
.B OfflineIMAP
must store both a UID folder ID.  The folder ID is
necessary so
.B OfflineIMAP
can detect a message moved to a different
folder.
.B OfflineIMAP
stores the UID (U= number) and an md5sum of the
foldername (FMD5= number) to facilitate this.
.TP
.B What is the speed of OfflineIMAP's sync?
.B OfflineIMAP
versions 2.0 and above contain a multithreaded system.  A good way to
experiment is by setting maxsyncaccounts to 3 and maxconnections to 3
in each account clause.
.IP
This lets OfflineIMAP open up multiple connections simultaneously.
That will let it process multiple folders and messages at once.  In
most cases, this will increase performance of the sync.
.IP
Don't set the number too high.  If you do that, things might actually
slow down as your link gets saturated.  Also, too many connections can
cause mail servers to have excessive load.  Administrators might take
unkindly to this, and the server might bog down.  There are many
variables in the optimal setting; experimentation may help.
.IP
An informal benchmark yields these results for my setup:
.IP
10 minutes with MacOS X Mail.app "manual cache"
.br
5 minutes with GNUS agent sync
.br
20 seconds with OfflineIMAP 1.x
.br
9 seconds with OfflineIMAP 2.x
.br
3 seconds with OfflineIMAP 3.x "cold start"
.br
2 seconds with OfflineIMAP 3.x "held connection"
.SH CONFORMING TO
.IP \(bu
Internet Message Access Protocol version 4rev1 (IMAP 4rev1) as
specified in RFC2060
.IP \(bu
Maildir as specified in
.UR http://www.qmail.org/qmail-manual-html/man5/maildir.html
http://www.qmail.org/qmail-manual-html/man5/maildir.html
.UE
and
.UR http://cr.yp.to/proto/maildir.html
http://cr.yp.to/proto/maildir.html.
.UE
.IP \(bu
Standard Python 2.2.1 as implemented on POSIX-compliant systems.
.SH NOTES
.SS DELETING LOCAL FOLDERS
.B OfflineIMAP
does a two-way synchronization.  That is, if you
make a change to the mail on the server, it will be propogated 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 (~/.offlineimap 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)
.SS COPYING MESSAGES BETWEEN FOLDERS
Normally, when you copy a message between folders or add a new message
to a folder locally,
.B 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,
.B 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.
.B OfflineIMAP
makes sure that the message was properly uploaded before deleting it,
so there should be no risk of data loss.
.SS MAILING LIST
There is an OfflineIMAP mailing list available.
.PP
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.
.SH BUGS
Should be reported to the author at the address specified below.
.SH COPYRIGHT
OfflineIMAP is Copyright (C) 2002 John Goerzen.
.PP
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.
.PP
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.
.PP
You should have received a copy of the GNU General Public License
along with this program; if not, write to:
.PP
Free Software Foundation, Inc.
.br
59 Temple Place
.br
Suite 330
.br
Boston, MA  02111-1307
.br
USA
.SH AUTHOR
.B OfflineIMAP,
its libraries, documentation, and all included files, except where
noted, was written by John Goerzen <jgoerzen@complete.org> and
copyright is held as stated in the COPYRIGHT section.
.PP
OfflineIMAP may be downloaded, and information found, from its
homepage via either Gopher or HTTP:
.PP
.UR gopher://quux.org/1/devel/offlineimap
gopher://quux.org/1/devel/offlineimap
.UE
.br
.UR http://quux.org/devel/offlineimap
http://quux.org/devel/offlineimap
.UE

.SH SEE ALSO
.BR mutt (1),
.BR python (1).
.\".BR bar (1),
.\".BR baz (1).
.\".br
.\"The programs are documented fully by
.\".IR "The Rise and Fall of a Fooish Bar" ,
.\"available via the Info system.
.\".SH AUTHOR
.\"This manual page was written by John Goerzen <jgoerzen@complete.org>,
.\"for the Debian GNU/Linux system (but may be used by others).