/brz/remove-bazaar

Browsing history

================

brz log

-------

The ``brz log`` command shows a list of previous revisions.

As with ``brz diff``, ``brz log`` supports the ``-r`` argument::

    % brz log -r 1000..          # Revision 1000 and everything after it

    % brz log -r ..1000          # Everything up to and including r1000

    % brz log -r 1000..1100      # changes from 1000 to 1100

    % brz log -r 1000            # The changes in only revision 1000

Viewing merged revisions

------------------------

As distributed VCS tools like Breezy make merging much easier than

it is in central VCS tools, the history of a branch may often contain

lines of development splitting off the mainline and merging back

in at a later time. Technically, the relationship between the

numerous revision nodes is known as a Directed Acyclic Graph or

DAG for short.

In many cases, you typically want to see the mainline first and drill

down from there. The default behaviour of log is therefore to show

the mainline and indicate which revisions have nested merged revisions.

To explore the merged revisions for revision X, use the following command::

  brz log -n0 -rX

To see all revisions and all their merged revisions::

  brz log -n0

Note that the -n option is used to indicate the number of levels to display

where 0 means all. If that is too noisy, you can easily adjust the number

to only view down so far. For example, if your project is structured with

a top level gatekeeper merging changes from team gatekeepers, ``brz log``

shows what the top level gatekeeper did while ``brz log -n2`` shows what

the team gatekeepers did. In the vast majority of cases though, ``-n0``

is fine.

Tuning the output

-----------------

The ``log`` command has several options that are useful for tuning

the output. These include:

 * ``--forward`` presents the log in chronological order, i.e. the

   most recent revisions are displayed last.

 * the ``--limit`` option controls the maximum number of revisions displayed.

See the online help for the log command or the User Reference for more

information on tuning the output.

Viewing the history for a file

------------------------------

It is often useful to filter the history so that it only

applies to a given file. To do this, provide the filename

to the ``log`` command like this::

  brz log foo.py

Viewing an old version of a file

--------------------------------

To get the contents of a file at a given version, use the

``cat`` command like this::

  brz cat -r X file

where ``X`` is the revision identifier and ``file`` is

the filename. This will send output to the standard output

stream so you'll typically want to pipe the output through

a viewing tool (like ``less`` or ``more``) or redirect it

like this::

  brz cat -r -2 foo.py | less

  brz cat -r 1 foo.py > /tmp/foo-1st-version.py

Graphical history viewers

-------------------------

History browsing is one area where GUI tools really make life easier.

Breezy has numerous plug-ins that provide this capability including

QBzr and brz-gtk. See `Using plugins <plugins.html>`_ for details on how to install

these if they are not already installed.

To use the graphical viewer from QBzr::

  brz qlog

To use the graphical viewer from brz-gtk::

  brz viz

``viz`` is actually a built-in alias for ``visualize`` so use the longer

command name if you prefer.