taskwarrior/doc/man/task-sync.5.in

.TH task-sync 5 2012-09-18 "${PACKAGE_STRING}" "User Manuals"

.SH NAME
task-sync \- A tutorial for the task(1) data synchronization capabilities.

.SH DESCRIPTION
Taskwarrior has built-in support for synchronization, which can be used to keep
two task databases up to date, regardless of which one is used.  This capability
can also be used to keep a backup copy of your task database on another machine.

Taskwarrior can use various protocols for transferring the data.

.SH HOW IT WORKS
If you were to manually attempt to keep two separate task databases up to date,
you would need to inspect both databases, and detect changes that occurred in
each one.  Those changes would need to be migrated to the other database, while
being careful not to miss a change, and not to confuse an 'add' in one with
a 'delete' in the other.

The synchronization feature does just this.  It can transfer task databases,
compare tasks, and apply changes where necessary.

.SH NEW COMMANDS
Taskwarrior has 'pull', 'push' and 'merge' commands which perform the steps
necessary to move files around and combine them.  In the common use case, you
would only need to use the 'merge' command.  These commands take an argument
that is a URI, which indicates where the remote database resides.

To be clear, the local database always refers to your ~/.task directory (unless
overridden), and the remote database is always specified by URI.

.SH MERGE
The merge command will fetch task data via URI and combine it with the local
task database.  The syntax is:

.br
.RS
task merge [<URI>]
.RE

The URI is optional if the
.B merge.default.uri
configuration variable is set.  The URI may point to a different directory, or
it may be a different computer.  Here is an example of the merge command:

.br
.RS
$ task merge ~/work/
.RE

This URI (~/work/) is a path name, which means the remote database is on the
same computer.  Taskwarrior will fetch the data from the URI, and merge it with
your local data in ~/.task.

When complete, you will be asked whether you would like to push the combined
data back to the remote location specified by the URI.  This is useful if you
are keeping two task databases synchronized, but it can be turned off.  See
CONFIGURATION.

Note that a merge operation is not atomically reversible.  You could however
run the 'task undo' command repeatedly to undo the effects.

.SH PUSH
The push command will copy the local task database to the specified URI.  The
syntax is:

.br
.RS
task push [<URI>]
.RE

The URI is optional if the
.B push.default.uri
configuration variable is set.  This command is useful for making backup copies
of your task database.

Note that the task files at the location specified by the URI are simply
overwritten, so don't expect any merging to occur.  Misused, push can be
dangerous.

.SH PULL
The pull command will copy a task database from a URI to the local task database
(~/.task by default).  The syntax is:

.br
.RS
task pull [<URI>]
.RE

The URI is optional if the
.B pull.default.uri
configuration variable is set.  This command is useful for restoring a backup
copy of your task database.

Note that your local task database files will be simply overwritten by the files
obtained from the location specified by the URI, so don't expect any merging to
occur.  Misused, pull can be dangerous.

.SH URI TYPES
The most basic URI is a path name on the local machine.  An example would be:

.br
.RS
/home/bob/.task/
.RE

All the other URIs allow access to remote machines.  The first uses SSH and scp
(either form can be used):

.br
.RS
ssh://[user@]host[:port]/absolute/path/to/.task/
.br
[user@]host:/absolute/path/to/.task/
.RE

In both cases paths are considered to be absolute. You can specify paths relative to the
users home directory as follows:

.br
.RS
ssh://[user@]host[:port]/.task/
.br
[user@]host:.task/
.RE

or even shorter

.br
.RS
[user@]host:.task/
.RE

Remark: Since taskwarrior simply calls the scp binary you can specify very much anything
that scp would accept, e.g. host configurations from ~/.ssh/config or ~username
expansion:

.br
.RS
ssh://configured-host/~[username]/.task/
.br
configured-host:~[username]/.task/
.RE


Rsync is another supported protocol that minimizes network traffic, by a clever
algorithm that doesn't copy files that have not changed:

.br
.RS
rsync://[user@]host.xz[:port]/path/to/.task/
.RE

Curl supports several protocols that can transfer data using HTTP, HTTPS and
FTP:

.br
.RS
http://host[:port]/path/to/.task/
.br
https://host[:port]/path/to/.task/
.br
ftp://[user@]host[:port]/path/to/.task/
.RE

You can use single quotes to encapsulate user names that contain delimiting
characters like '@', '/' or ':', e.g.:

.br
.RS
ssh://'user@name'@host/
.RE

Remember to escape the quotes on your shell:

.br
.RS
$ task push ftp://\'user@name\':host/
.RE

.SH CONFLICTS
When modifications on the local and remote machine conflict, for example if
both machines change the project name of the same task to different values,
then Taskwarrior automatically selects the most recent change.  Thus, there
are no conflicts.

.SH EXAMPLE - Backup on another machine
One very good use of 'push' is to make backup copies of your task database in
another location.  Suppose your task database is kept in the usual place, in
the ~/.task directory, and you wanted to make a backup copy in ~/backup.  You
would use this command:

.br
.RS
$ task push ~/backup/
.RE

This would copy the files in ~/.task to ~/backup, overwriting the files that
were already in ~/backup.  To backup your files to another machine, you could
use:

.br
.RS
$ task push user@host:backup
.RE

This could be improved by setting the
.B push.default.uri
configuration variable and then relying on the default, like this:

.br
.RS
$ task config push.default.uri user@host:backup
.RE

and then you need only run the push command:

.br
.RS
$ task push
.RE

and the default push URI will be used.  If you wanted to restore a backup, you
simply use the pull command instead:

.br
.RS
$ task pull user@host:backup
.RE

This can be simplified by setting the
.B pull.default.uri
configuration variable and then relying on the default, like this:

.br
.RS
$ task config pull.default.uri user@host:backup
.RE

Note that pull and push will blindly overwrite the task files without any
merging.  Be careful.

.SH EXAMPLE - Keeping two task databases synchronized
The most common synchronization will be to keep two task databases synchronized
on different machines.  Here is a full example, including setup that illustrates
this.

Suppose there are two machines, named 'local' and 'remote', for simplicity.
Taskwarrior is installed on both machines.  The different machines are
indicated here by the prompt.  Suppose Alice enters two tasks on her local
machine:

.br
.RS
local> task add Deliver the new budget proposal due:tuesday
.br
local> task add Set up a meeting with Bob
.RE

Then later adds a task on the remote machine:

.br
.RS
remote> task add Present the budget proposal at the big meeting due:thursday
.RE

Now on the local machine, Alice merges the two task databases:

.br
.RS
local> task merge alice@remote:.task
.br
Would you like to push the changes to 'alice@remote:.task'?  Y
.RE

Taskwarrior has combined the two task databases on local, then pushed the
changes back to remote.  Now suppose Alice changes the due date for task 1
on remote:

.br
.RS
remote> task 1 due:wednesday
.RE

Now on the local machine, Alice sets up a default URI and autopush:

.br
.RS
local> task config merge.default.uri alice@remote:.task
.br
local> task config merge.autopush yes
.RE

Now Alice can simply run merge to make sure that the new due date is copied to
the local machine:

.br
.RS
local> task merge
.RE

This time the URI is determined automatically, and after the merge the files are
pushed back to the remote machine.  In a similar way, the remote machine can
also be configured to merge from the local machine and push back to it.  Then it
is just a matter of Alice remembering to merge now and then, from either
machine, to have her data in two (or even more) places.

.SH CONFIGURATION
By setting these configuration variables, it is possible to simplify the
synchronization commands, by relying on the defaults or alias names.

.br
.B merge.autopush=yes|no|ask
.RS
This controls whether the automatic push after a merge is performed, not
performed, or whether the user is asked every time.  The default value is 'ask'.
.RE

.br
.B merge.default.uri=<uri>
.RS
Sets a default URI so that just the 'task merge' command be run without the
need to retype the URI every time. You can also use this configuration scheme
to set alias names, e.g. set merge.desktop.uri and run 'task merge desktop'.
.RE

.br
.B push.default.uri=<uri>
.RS
Sets a default URI so that just the 'task push' command be run without the
need to retype the URI every time. You can also use this configuration scheme
to set alias names, e.g. set push.desktop.uri and run 'task push desktop'.
.RE

.br
.B pull.default.uri=<uri>
.RS
Sets a default URI so that just the 'task pull' command be run without the
need to retype the URI every time. You can also use this configuration scheme
to set alias names, e.g. set pull.desktop.uri and run 'task pull desktop'.
.RE

Note that, when using SSH/scp, hostnames will be expanded due to the ssh 
configuration file ~/.ssh/config.

.SH EXTERNAL DEPENDENCIES
Depending on the URI protocols used, the utilities 'scp', 'rsync' and 'curl'
must be installed and accessible via the $PATH environment variable.

If you have deleted your ~/.task/undo.data file to save space, you will be
unable to merge.  The change transactions stored in the undo.data file are
used for synchronization.

.SH "CREDITS & COPYRIGHTS"
Copyright (C) 2006 \- 2012 P. Beckingham, F. Hernandez.

The sync capabilities were written by J. Schlatow.
Parts copyright (C) 2010 - 2012 J. Schlatow.

Taskwarrior is distributed under the MIT license. See
http://www.opensource.org/licenses/mit-license.php for more information.

.SH SEE ALSO
.BR task(1),
.BR taskrc(5),
.BR task-faq(5),
.BR task-color(5),
.BR task-tutorial(5),
.BR ssh_config(5)

For more information regarding task, the following may be referenced:

.TP
The official site at
<http://taskwarrior.org>

.TP
The official code repository at
<git://tasktools.org/task.git/>

.TP
You can contact the project by writing an email to
<support@taskwarrior.org>

.SH REPORTING BUGS
.TP
Bugs in task may be reported to the issue-tracker at
<http://taskwarrior.org>