Pro Gitと入門Gitと入門gitと実用GitでGitの復習 無名ブランチ(detached HEAD)からの復活編

$ git checkout -b nobra
Switched to a new branch 'nobra'

$ touch nobra
$ git add nobra
$ git commit -m "Add nobra"
[nobra d62e4cb] Add nobra
 0 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 nobra

$ git g
 * d62e4cb  (HEAD, nobra, master) Add nobra
 * 7ab5db8  (topic) Add message line 3
 * cf6c3d6  Add message line 2
 * 38f8aff  Add message line 1
 * 93b8e52  Add message line 4
 * 0b91a9f  Add message line 5
 * 15f636f  Add line number
 * fa9eabc  first commit

$ git br
   master d62e4cb Add nobra
 * nobra  d62e4cb Add nobra
   topic  7ab5db8 Add message line 3

$ git ch d62e4cb
Note: checking out 'd62e4cb'.

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 d62e4cb... Add nobra

$ git br
 * (no branch) d62e4cb Add nobra
   master      d62e4cb Add nobra
   nobra       d62e4cb Add nobra
   topic       7ab5db8 Add message line 3

$ echo "no branch" >> nobra
$ git add nobra
$ git com "Add message nobra"
[detached HEAD e45c786] Add message nobra
 1 files changed, 1 insertions(+), 0 deletions(-)

$ echo "detached HEAD" >> nobra
$ git add nobra
$ git com "Add message nobra"
[detached HEAD 3aec83c] Add message nobra
 1 files changed, 1 insertions(+), 0 deletions(-)

$ git g
 * 3aec83c  (HEAD) Add message nobra
 * e45c786  Add message nobra
 * d62e4cb  (nobra, master) Add nobra
 * 7ab5db8  (topic) Add message line 3
 * cf6c3d6  Add message line 2
 * 38f8aff  Add message line 1
 * 93b8e52  Add message line 4
 * 0b91a9f  Add message line 5
 * 15f636f  Add line number
 * fa9eabc  first commit

$ git checkout master
Previous HEAD position was 3aec83c... Add message nobra
Switched to branch 'master'

$ git g
 * d62e4cb  (HEAD, nobra, master) Add nobra
 * 7ab5db8  (topic) Add message line 3
 * cf6c3d6  Add message line 2
 * 38f8aff  Add message line 1
 * 93b8e52  Add message line 4
 * 0b91a9f  Add message line 5
 * 15f636f  Add line number
 * fa9eabc  first commit

$ git reflog
...
d62e4cb HEAD@{6}: checkout: moving from 3aec83cdbfea0b1e96cf3c48937ab84eae1f4ec0 to nobra
3aec83c HEAD@{7}: commit: Add message nobra
e45c786 HEAD@{8}: commit: Add message nobra
...

$ git g
 * d62e4cb  (HEAD, nobra, master) Add nobra
 * 7ab5db8  (topic) Add message line 3
 * cf6c3d6  Add message line 2
 * 38f8aff  Add message line 1
 * 93b8e52  Add message line 4
 * 0b91a9f  Add message line 5
 * 15f636f  Add line number
 * fa9eabc  first commit

$ git reflog
...
d62e4cb HEAD@{8}: checkout: moving from 3aec83cdbfea0b1e96cf3c48937ab84eae1f4ec0 to nobra
3aec83c HEAD@{9}: commit: Add message nobra
e45c786 HEAD@{10}: commit: Add message nobra
d62e4cb HEAD@{11}: checkout: moving from nobra to d62e4cb

$ git branch --f nobra HEAD@{9}

$ git g
 * 3aec83c  (nobra) Add message nobra
 * e45c786  Add message nobra
 * d62e4cb  (HEAD, master) Add nobra
 * 7ab5db8  (topic) Add message line 3
 * cf6c3d6  Add message line 2
 * 38f8aff  Add message line 1
 * 93b8e52  Add message line 4
 * 0b91a9f  Add message line 5
 * 15f636f  Add line number
 * fa9eabc  first commit

$ git merge nobra
Updating d62e4cb..3aec83c
Fast-forward
 nobra |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

$ git g
 * 3aec83c  (HEAD, nobra, master) Add message nobra
 * e45c786  Add message nobra
 * d62e4cb  Add nobra
 * 7ab5db8  (topic) Add message line 3
 * cf6c3d6  Add message line 2
 * 38f8aff  Add message line 1
 * 93b8e52  Add message line 4
 * 0b91a9f  Add message line 5
 * 15f636f  Add line number
 * fa9eabc  first commit