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vc-diff). With a prefix argument, prompt for two
revisions of the current VC fileset and compare them. You can also
call this command from a Dired buffer (see Dired).
vc-root-diff). With a prefix argument, prompt for two
revisions and compare their trees.
vc-revision-other-window).
vc-annotate).
C-x v = (vc-diff) displays a diff which compares
each work file in the current VC fileset to the version(s) from which
you started editing. The diff is displayed in another window, in a
Diff mode buffer (see Diff Mode) named *vc-diff*. The
usual Diff mode commands are available in this buffer. In particular,
the g (revert-buffer) command performs the file
comparison again, generating a new diff.
To compare two arbitrary revisions of the current VC fileset, call
vc-diff with a prefix argument: C-u C-x v =. This
prompts for two revision IDs (see VCS Concepts), and displays a
diff between those versions of the fileset. This will not work
reliably for multi-file VC filesets, if the version control system is
file-based rather than changeset-based (e.g., CVS), since then
revision IDs for different files would not be related in any
meaningful way.
Instead of the revision ID, some version control systems let you specify revisions in other formats. For instance, under Bazaar you can enter ‘date:yesterday’ for the argument to C-u C-x v = (and related commands) to specify the first revision committed after yesterday. See the documentation of the version control system for details.
If you invoke C-x v = or C-u C-x v = from a Dired buffer (see Dired), the file listed on the current line is treated as the current VC fileset.
M-x vc-ediff works like C-x v =, except that it uses an Ediff session. See Ediff.
C-x v D (vc-root-diff) is similar to C-x v =, but
it displays the changes in the entire current working tree (i.e., the
working tree containing the current VC fileset). If you invoke this
command from a Dired buffer, it applies to the working tree containing
the directory.
You can customize the diff options that C-x v = and
C-x v D use for generating diffs. The options used are taken
from the first non-nil value amongst the variables
vc-backend-diff-switches, vc-diff-switches, and
diff-switches (see Comparing Files), in that order. Here,
backend stands for the relevant version control system,
e.g., bzr for Bazaar. Since nil means to check the
next variable in the sequence, either of the first two may use the
value t to mean no switches at all. Most of the
vc-backend-diff-switches variables default to nil,
but some default to t; these are for version control systems
whose diff implementations do not accept common diff options,
such as Subversion.
To directly examine an older version of a file, visit the work file
and type C-x v ~ revision <RET>
(vc-revision-other-window). This retrieves the file version
corresponding to revision, saves it to
filename.~revision~, and visits it in a separate
window.
Many version control systems allow you to view files annotated
with per-line revision information, by typing C-x v g
(vc-annotate). This creates a new buffer (the “annotate
buffer”) displaying the file's text, with each line colored to show
how old it is. Red text is new, blue is old, and intermediate colors
indicate intermediate ages. By default, the color is scaled over the
full range of ages, such that the oldest changes are blue, and the
newest changes are red.
When you give a prefix argument to this command, Emacs reads two arguments using the minibuffer: the revision to display and annotate (instead of the current file contents), and the time span in days the color range should cover.
From the annotate buffer, these and other color scaling options are available from the ‘VC-Annotate’ menu. In this buffer, you can also use the following keys to browse the annotations of past revisions, view diffs, or view log entries: