[git] fatal: This operation must be run in a work tree

I get this error when I try to change branch.

Probably I will give some information of the commands at

/path/to/git/repo/.

upon command:

git branch

I get following output

* V1.5
  V2.0
  master

And when I try the command

git checkout V2.0

I get following output:

fatal: This operation must be run in a work tree

config file contents:

cat config 
[core]
        repositoryformatversion = 0
        filemode = true
        bare = true
[remote "origin"]
        url = /path/to/git/repo/.git

You repository is bare, i.e. it does not have a working tree attached to it. You can clone it locally to create a working tree for it, or you could use one of several other options to tell Git where the working tree is, e.g. the --work-tree option for single commands, or the GIT_WORK_TREE environment variable. There is also the core.worktree configuration option but it will not work in a bare repository (check the man page for what it does).

# git --work-tree=/path/to/work/tree checkout master
# GIT_WORK_TREE=/path/to/work/tree git status