I'm aware that there are VCS plugins for Vim. I made this because I like
to use the same interface as the command line tools and without
restrictions. Filename completion and piping works, and Vim command line
expands % to current filename. Inside Vim, :Bzr command works just like
"bzr" from shell. Commands :Git, :Hg and :Svn work similarly. Examples:

   :Bzr log -l20
   :Bzr diff -c -1
   :Bzr annotate %
   :Bzr help merge

   :Git shortlog -ns %
   :Hg heads
   :Svn info

   :Shell ls -a | column