As to be expected in a revision control system, many options are of the form ‘-flag[rev]’, where flag is a single letter (e.g., ‘r’). If ommitted, rev defaults to the latest revision on the default branch. A revision can be specified in many ways:
Straightforward dot-notation, where br specifies the branch.
Like br.n, using the default branch.
Like br.n, using the a command-specific computation of
n, given the current tip i.
For ci (see ci), n would be
i + 1,
while for other commands n would be simply i.
This is the symbolic name of a revision, as assigned previously by a
ci -n or
ci -N command.
The command computes the effective revision by examining the values of keyword expansions in the working file.
For commands that accept a range of revisions, the syntax is
rev1:rev2, i.e., two revisions
(specified as described above) separated by a colon.