View

Basic

Show local branches.

$ git branch

  foo
* bar
  master

Get the current branch.

$ git branch --show-current
bar

Verbose

Show local branches with references to the remote.

$ git branch -v

  foo                                                    4c677a0 [gone] Some commit message
* bar                                                    a89446e Another message
  master                                                 5680e85 Yet another commit message

Remotes

Show only remote branches.

$ git branch -r

  origin/bar
  origin/HEAD -> origin/master
  origin/master

You can also run this with the verbose flag to which commit each points to.

$ git branch -r -v
  origin/bar                                 a89446e Another message
  origin/HEAD                                -> origin/master
  origin/master                              5680e85 Yet another commit message

All

View both local and remote branch references.

$ git branch -a

  foo
* bar
  master
  remotes/origin/bar
  remotes/origin/baz
  remotes/origin/HEAD -> origin/master
  remotes/origin/master