Re: [O] [SYNC] How do you sync your org-mode files between n devices (n > 2)

[Suvayu Ali]

Just a few typo/editorial comments.

On Thu, Sep 05, 2013 at 02:31:42PM +0200, Alan Schmitt wrote:
> 
> * Synchronizing org files with Unison
> 
> This describes how to synchronize org files using the 
> [[http://www.cis.upenn.edu/~bcpierce/unison/][Unison file synchronizer]],
> as well as how to configure it to use an external tool to merge conflicting
> edits.
> 
> ** Prerequisites
> 
> You should have Unison up and running. Binaries can be found 
> [[http://www.cis.upenn.edu/~bcpierce/unison/download.html][here]] and the
> documentation is 
> [[http://www.cis.upenn.edu/~bcpierce/unison/download/releases/stable/unison-manual.html][here]].
> 
> ** Synchronization
> 
> Unison is a file synchronizer, thus it may be used to synchronize org files. 
> To
> configure Unison, on uses a /profile/ which states where the things to

on uses -> one uses

> synchronize are as well as some options. Assuming I want to synchronize the
> files in ~/Users/schmitta/dir1~ and ~/Users/schmitta/dir2~, the profile would
> look like this
> 
> #+BEGIN_EXAMPLE
> root = /Users/schmitta/dir1
> root = /Users/schmitta/dir2
> #+END_EXAMPLE
> 
> In most cases Unison will be used with a remote machine. The local machine is
> called the /client/ and the remote one the /server/. For such remote
> synchronization, the ~unison~ binary must be installed in the server as
> well. The simplest way to connect to the machine is using ssh. One should 
> check
> that unison can be found there by doing ~ssh address@hidden unison -version~. 
> If
> ~unison~ cannot be found in the path, one may set the ~servercmd~ option as
> indicated in the next example.
> 
> (Please see the 
> [[http://www.cis.upenn.edu/~bcpierce/unison/download/releases/stable/unison-manual.html#roots][manual
>  section on roots]] for further details.)
> 
> #+BEGIN_EXAMPLE
> root = /Users/schmitta/dir1
> root = ssh://address@hidden/relative/path/to/dir2
> 
> servercmd = /usr/bin/unison
> #+END_EXAMPLE
> 
> ** Merging
> 
> As Unison works on the level of files, it will trigger a /conflict/ if both
> files have changed since the last synchronization. In that case one can only
> choose which file to keep, which is not satisfying. Unison offers the

Maybe satisfactory is better than satisfying?

> possibility to use external tools to merge the files. There is an 
> [[http://www.cis.upenn.edu/~bcpierce/unison/download/releases/stable/unison-manual.html#merge][extensive
> manual section]] regarding this, we'll just describe how to use emacs and 
> ediff to
> do it.
> 
> For better merging, we will ask unison to keep the last synchronized version 
> of
> every org file on the client; this way we can use ediff with ancestor. These
> ~currentbackup~ files may live alongside the synchronized files (with names of
> the form ~.bak.version.name~, which is configurable) or in a central location.
> 
> Here is the modified configuration file.
> 
> #+BEGIN_EXAMPLE
> root = /Users/schmitta/dir1
> root = ssh://address@hidden/relative/path/to/dir2
> 
> servercmd = /usr/bin/unison
> 
> backupcurrent = Name *.org
> backuplocation = local
> maxbackups = 0
> 
> merge = Name *.org -> emacsclient -c --eval '(ediff-merge-files-with-ancestor 
> "CURRENT1" "CURRENT2" "CURRENTARCH" nil "NEW")'
> 
> #+END_EXAMPLE
> 
> The ~backupcurrent~ option tells unison to keep a backup of the last
> synchronized version of ever file with an ~org~ extension. The location of the

ever file -> every file

> backup should be local (alongside the file). Finally, no other backup should 
> be
> created.
> 
> Next follows the merge command. For every org file in conflict, use the 
> command
> that launches a new emacs frame calling the ediff with ancestor function. The
> ~CURRENT1~, ~CURRENT2~, and ~CURRENTARCH~ strings are  replaced with the file
> from the first root, the file from the second root, and the last synchronized
> version. The ~NEW~ file is where Unison expects the file to be saved (which 
> will
> be done by the ediff session).
> 
> Thus, when an org file has been modified on both hosts, an ediff session will 
> be
> launched in a new frame. Closing the frame will make Unison commit the merge 
> (it
> waits until the command has finished).
> 
> If one does not want to use backups, it's possible to use the simpler ediff
> (without ancestor) command as follows.
> 
> #+BEGIN_EXAMPLE
> root = /Users/schmitta/dir1
> root = ssh://address@hidden/relative/path/to/dir2
> 
> servercmd = /usr/bin/unison
> 
> merge = Name *.org -> emacsclient -c --eval '(ediff-merge-files "CURRENT1" 
> "CURRENT2" nil "NEW")'
> 
> #+END_EXAMPLE

This a very clear and complete write-up.  Thanks a lot Alan!

:)

-- 
Suvayu

Open source is the future. It sets us free.