Checkout

Initialize Git repository and VB for test:

$ git init
Initialized empty Git repository in * (glob)
$ touch README.txt
$ git add .
$ git commit --message 'First commit' > /dev/null
$ vb init

vb checkout creates a branch and make a clone repository to work with it. Working copy of the root repository is not changed. vb checkout takes argument like git branch:

$ vb checkout branch-a
$ git branch
  branch-a
* master
$ cd .vb/branch-a
$ git branch
* branch-a
  master
$ git remote
locmain
$ cd ../..

Branch to be based on is default to the currently checked out one. But it can be specified:

$ echo 'edit' > README.txt
$ git commit --all --message 'Second commit' > /dev/null
$ vb checkout branch-b branch-a
$ git branch
  branch-a
  branch-b
* master
$ git log --format=oneline
* Second commit* (glob)
* First commit* (glob)
$ cd .vb/branch-b
$ git branch
* branch-b
  master
$ git log --format=oneline
* First commit* (glob)
$ cd ../..

Existing branch can be used. In that case, repository is just checked out in .vb/BRANCH:

$ git branch branch-c
$ vb checkout --existing branch-c
$ cd .vb/branch-c
$ git branch
* branch-c
  master
$ cd ../..

Passing --existing for non-existing branch fails:

$ vb checkout --existing non-existing-branch
Branch 'non-existing-branch' does not exist
[1]

If repository at .vb/BRANCH already exist, it does not do anything:

$ vb checkout branch-a
.vb/branch-a already exists
$ vb checkout --existing branch-c
.vb/branch-c already exists