Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 562 — #588
i
i
i
i
i
i
i
i
23.3 Introduction to Unison
Unison is an excellent solution for synchronizing and transferring entire di-
rectory trees. The synchronization is performed in both directions and can
be controlled by means of an intuitive graphical front-end. A console ver-
sion can also be used. The synchronization can be automated so interaction
with the user is not required, but experience is necessary.
23.3.1 Requirements
Unison must be installed on the client as well as on the server. In this con-
text, the term server refers to a second, remote host (unlike CVS, explained
in Section 23.1.2 on page 557).
In the following section, Unison is used together with ssh. In this case, an
SSH client must be installed on the client and an SSH server must be in-
stalled on the server.
23.3.2 Using Unison
The approach used by Unison is the association of two directories (roots)
with each other. This association is symbolic — it is not an online connec-
tion. In this example, the directory layout is as follows:
Client: /home/tux/dir1
Server: /home/geeko/dir2
You want to synchronize these two directories. The user is known as tux on
the client and as geeko on the server. The first thing to do is to test if the
client-server communication works:
unison -testserver /home/tux/dir1 ssh://geeko@server//homes/geeko/dir2
The most frequently encountered problems are:
The Unison versions used on the client and server are not compatible.
The server does not allow SSH connections.
562 23.3. Introduction to Unison