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. See Using plugins for details on how to install these if they are not already installed.

To use the graphical viewer from QBzr:

brz qlog