% git checkout b1
error: pathspec 'b1' did not match any file(s) known to git.
% git checkout -b b1
Switched to a new branch 'b1'
% git push origin b1
Total 0 (delta 0), reused 0 (delta 0)
To file:///tmp/crap.git
 * [new branch]      b1 -> b1
% git pull --rebase
There is no tracking information for the current branch.
Please specify which branch you want to rebase against.
See git-pull(1) for details.

    git pull <remote> <branch>

If you wish to set tracking information for this branch you can do so with:

    git branch --set-upstream-to=origin/<branch> b1

% git branch --set-upstream-to=origin/b1 b1
Branch b1 set up to track remote branch b1 from origin.
% git pull --rebase
Current branch b1 is up to date.
% git checkout master
Switched to branch 'master'
Your branch is up-to-date with 'origin/master'.
% git checkout -b b2
Switched to a new branch 'b2'
% git branch --set-upstream-to=origin/b2 b2
error: the requested upstream branch 'origin/b2' does not exist
hint:
hint: If you are planning on basing your work on an upstream
hint: branch that already exists at the remote, you may need to
hint: run "git fetch" to retrieve it.
hint:
hint: If you are planning to push out a new local branch that
hint: will track its remote counterpart, you may want to use
hint: "git push -u" to set the upstream config as you push.
% git push origin b2
Total 0 (delta 0), reused 0 (delta 0)
To file:///tmp/crap.git
 * [new branch]      b2 -> b2
% git branch --set-upstream-to=origin/b2 b2
Branch b2 set up to track remote branch b2 from origin.
% git pull --rebase
Current branch b2 is up to date.
% touch a b c
% git add a b c
% git commit -a
[b2 0313b0c] add a b c
 3 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 a
 create mode 100644 b
 create mode 100644 c
% git push origin
Counting objects: 2, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (2/2), 240 bytes | 0 bytes/s, done.
Total 2 (delta 0), reused 0 (delta 0)
To file:///tmp/crap.git
   05572d5..0313b0c  b2 -> b2
% git checkout b1
Switched to branch 'b1'
Your branch is up-to-date with 'origin/b1'.
% echo this was the first one > first
% git add first
% git commit -a
[b1 436dd38] set up b1
 1 file changed, 1 insertion(+)
 create mode 100644 first
% git push
Counting objects: 3, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 291 bytes | 0 bytes/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To file:///tmp/crap.git
   05572d5..436dd38  b1 -> b1
% git log | more
commit 436dd3892cd7420dcd7eff487a95860fe3cb4d57
Date:   Mon Feb 6 08:54:42 2017 -0800

    set up b1

commit 05572d5a3a8b4038297920d1297f0d1961b1776e
Date:   Mon Feb 6 08:51:23 2017 -0800

    start
% git checkout b2
Switched to branch 'b2'
Your branch is up-to-date with 'origin/b2'.
% ls
a	b	c	empty
% git merge 436dd3892cd7420dcd7eff487a95860fe3cb4d57
Merge made by the 'recursive' strategy.
 first | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 first
% git push origin
Counting objects: 2, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (2/2), 291 bytes | 0 bytes/s, done.
Total 2 (delta 1), reused 0 (delta 0)
To file:///tmp/crap.git
   0313b0c..e7cf7db  b2 -> b2
% git log | more
commit e7cf7dbff37ffafc98720972a38cd11545be41c4
Merge: 0313b0c 436dd38
Date:   Mon Feb 6 08:55:57 2017 -0800

    Merge commit '436dd3892cd7420dcd7eff487a95860fe3cb4d57' into b2

commit 436dd3892cd7420dcd7eff487a95860fe3cb4d57
Date:   Mon Feb 6 08:54:42 2017 -0800

    set up b1

commit 0313b0c4ee75aeb298f67e584771ce391c45a028
Date:   Mon Feb 6 08:53:34 2017 -0800

    add a b c

commit 05572d5a3a8b4038297920d1297f0d1961b1776e
Date:   Mon Feb 6 08:51:23 2017 -0800

% ls
a	b	c	empty	first
% git status | more
On branch b2
Your branch is up-to-date with 'origin/b2'.
nothing to commit, working tree clean
% git checkout 436dd3892cd7420dcd7eff487a95860fe3cb4d57
Note: checking out '436dd3892cd7420dcd7eff487a95860fe3cb4d57'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b <new-branch-name>

HEAD is now at 436dd38... set up b1
% ls
empty	first
% git status | more
HEAD detached at 436dd38
nothing to commit, working tree clean
% ls
empty	first
% git log | more
commit 436dd3892cd7420dcd7eff487a95860fe3cb4d57
Date:   Mon Feb 6 08:54:42 2017 -0800

    set up b1

commit 05572d5a3a8b4038297920d1297f0d1961b1776e
Date:   Mon Feb 6 08:51:23 2017 -0800

    start
% git checkout b2
Previous HEAD position was 436dd38... set up b1
Switched to branch 'b2'
Your branch is up-to-date with 'origin/b2'.
% git log | more
commit e7cf7dbff37ffafc98720972a38cd11545be41c4
Merge: 0313b0c 436dd38
Date:   Mon Feb 6 08:55:57 2017 -0800

    Merge commit '436dd3892cd7420dcd7eff487a95860fe3cb4d57' into b2

commit 436dd3892cd7420dcd7eff487a95860fe3cb4d57
Date:   Mon Feb 6 08:54:42 2017 -0800

    set up b1

commit 0313b0c4ee75aeb298f67e584771ce391c45a028
Date:   Mon Feb 6 08:53:34 2017 -0800

    add a b c

commit 05572d5a3a8b4038297920d1297f0d1961b1776e
Date:   Mon Feb 6 08:51:23 2017 -0800

%