出庫

git clone 與 git pull的區別

[[email protected] a]$ git init

[[email protected] a]$ git clone [remote_repo_path]

# On branch master

#

# Initial commit

#

# Untracked files:

#   (use "git add <file>..." to include in what will be committed)

#

#       test/

nothing added to commit but untracked files present (use "git add" to track)

[[email protected] a]$ git log

fatal: bad default revision 'HEAD'

[[email protected] a]$ git branch

[[email protected] a]$ git init

[[email protected] a]$ git pull [remote_repo_path]

[[email protected] b]$ git status

# On branch master

nothing to commit (working directory clean)

[[email protected] b]$ git log

commit 4ab6b6d53b77ba41ca94a443a6d6cf00acdfcb42

…….

[[email protected] git_study]$diff -r a/.git/ b/.git/

Only in b/.git/: FETCH_HEAD

Binary files a/.git/index and b/.git/index differ

Only in b/.git/: logs

Only in b/.git/objects/pack: pack-9a714c6fd30c1addc0648e809907bb09ebff0230.idx

Only in b/.git/objects/pack: pack-9a714c6fd30c1addc0648e809907bb09ebff0230.pack

Only in b/.git/refs/heads: master

[[email protected] b]$ git branch

* master

由上可見，git clone只是簡單的把遠端庫中的內容拷貝到本地，並沒有建立分支，因此拷過來的內容還沒有加入tracking，也沒有log資訊；而git pull自動建立了master分支，內容（包括log）與遠端庫一致。

即使是git clone，如果要進行庫操作git init也是不可缺少的：

[[email protected] c]$ git clone ssh://[email protected]:7999/gpon/test.git

Cloning into 'test'...

remote: Counting objects: 671, done.

remote: Compressing objects: 100% (316/316), done.

remote: Total 671 (delta 287), reused 612 (delta 263)

Receiving objects: 100% (671/671), 801.00 KiB | 88 KiB/s, done.

Resolving deltas: 100% (287/287), done.

[[email protected] c]$ git status

fatal: Not a git repository (or any parent up to mount point /home)

Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

[[email protected] c]$ git log

fatal: Not a git repository (or any parent up to mount point /home)

Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

[[email protected] c]$

基本入庫

修改一個檔案

假設修改了a.txt。

使用git status可以看到Changes not staged for commit下面有一個modified的檔案

[[email protected] a]$ git status

# On branch master

# Changes not staged for commit:

#   (use "git add <file>..." to update what will be committed)

#   (use "git checkout -- <file>..." to discard changes in working directory)

#

#       modified:   a.txt

#

no changes added to commit (use "git add" and/or "git commit -a")git add

[[email protected] a]$ git add a.txt

[[email protected] a]$ git status

# On branch master

# Changes to be committed:

#   (use "git reset HEAD <file>..." to unstage)

#

#       modified:   a.txt

#

使用git commit後，git status內沒有內容，git log可以看到新增一條log

[[email protected] a]$ git commit -m "modify a.txt"

[master 22316f1] modify a.txt

 1 file changed, 1 insertion(+)

[[email protected] a]$ git status

# On branch master

nothing to commit(working directory clean)

[[email protected] a]$ git log

commit 22316f1e002341ec33f58d7c82730527625237c0

Author:

Date:   Sun Feb 2 10:49:03 2014 +0800

modify a.txt

使用git remote add，新增一個remote（本命令只需使用一次）

[[email protected] a]$ git remote add origin2 ssh://xxx

使用git push，將本地修改推送到遠端庫

[[email protected] a]$ git push

Counting objects: 5, done.

Delta compression using up to 4 threads.

Compressing objects: 100% (2/2), done.

Writing objects: 100% (3/3), 338 bytes, done.

Total 3 (delta 0), reused 0 (delta 0)

To ssh://[email protected]:7999/gpon/test.git

   ed7f63f..22316f1  master -> master

增加一個檔案

使用git status可以看到一個untracked files

[[email protected] a]$ git status

# On branch master

# Untracked files:

#   (use "git add <file>..." to include in what will be committed)

#

#       a2.txt

nothing added to commit but untracked files present (use "git add" to track)

使用git add後，再用git status檢視有一個Changes to be commited的檔案

[[email protected] a]$ git add a2.txt

[[email protected] a]$ git status

# On branch master

# Changes to be committed:

#   (use "git reset HEAD <file>..." to unstage)

#

#       new file:   a2.txt

#

使用git commit後，git status內沒有內容，git log增加了一條log

[[email protected] a]$ git commit -m "add a2.txt"

[master 21a90f2] add a2.txt

 1 file changed, 1 insertion(+)

 create mode 100644 a2.txt

[[email protected] a]$ git status

# On branch master

nothing to commit (working directory clean)

[[email protected] a]$ git log

commit 21a90f2562c826230adfbcc5a1332a7f081344a9

Author:

Date:   Sun Feb 2 11:01:06 2014 +0800

    add a2.txt

直接使用git push將本地修改推送到遠端庫

[[email protected] a]$ git push

Counting objects: 4, done.

Delta compression using up to 4 threads.

Compressing objects: 100% (2/2), done.

Writing objects: 100% (3/3), 284 bytes, done.

Total 3 (delta 1), reused 0 (delta 0)

To ssh://[email protected]:7999/gpon/test.git

   22316f1..21a90f2  master -> master

刪除一個檔案

[[email protected] a]$ git rm a2.txt

rm 'a2.txt'

[[email protected] a]$ git status

# On branch master

# Changes to be committed:

#   (use "git reset HEAD <file>..." to unstage)

#

#       deleted:    a2.txt

#

[[email protected] a]$ git commit -m "delete a2.txt"

[master 3764a36] delete a2.txt

 1 file changed, 1 deletion(-)

 delete mode 100644 a2.txt

[[email protected] a]$ git push

Counting objects: 3, done.

Delta compression using up to 4 threads.

Compressing objects: 100% (2/2), done.

Writing objects: 100% (2/2), 227 bytes, done.

Total 2 (delta 1), reused 0 (delta 0)

To ssh://[email protected]:7999/gpon/test.git

   21a90f2..3764a36  master -> master

小結

從上述操作可以看到，git的操作分為三個層次，stage、local repo和remote repo，其中git add和git rm用於將一個檔案的修改（包括建立和刪除）新增到stage，git commit用於將stage中記錄的修改入庫到local repo，git push則將本地庫的修改推送到遠端庫，每個層次的操作都以前一層次的內容為基礎——即stage內有內容才可以commit，local repo有內容才可以push。

入庫撤銷操作

git reset

使用git與svn很大的一個不同，是在開發過程中先在本地進行一系列的入庫（僅commit不push），待整個功能確認完成後，一次性推送到遠端庫。當然在本地庫操作過程中，不可避免地會碰到需要撤銷本地庫入庫的情況。

git reset撤銷stage和local repo的修改

使用git reset撤銷commit，保留本地檔案的修改和add的資訊。

[[email protected] a]$ git log

commit 8fd3cf3da8dcf0663150b29b4b7d844e83af097c

    feature 1.3

commit 644ae1487dfbb6b81aae19049af0a97b93baa52e

    feature 1.2

commit a37a3c5f6844aac058530f657c540221ef36807e

    feature 1.1

使用git reset [3764a36206944735ea3ee461c254e4c194b160ce]，可以將commit資訊回退到delete a2.txt時的狀態——log最後一條是“delete a.txt”，status中的a.txt的修改還沒有加入到stage：

[[email protected] a]$ git log

commit 3764a36206944735ea3ee461c254e4c194b160ce

    delete a2.txt

 [[email protected] a]$ git status

# On branch master

# Changes not staged for commit:

#   (use "git add <file>..." to update what will be committed)

#   (use "git checkout -- <file>..." to discard changes in working directory)

#

#       modified:   a.txt

#

no changes added to commit (use "git add" and/or "git commit -a")

然後按照基本入庫步驟將feature1.1/feature1.2/feature1.3作為function1一次commit即可

[[email protected] a]$ git add a.txt

[[email protected] a]$ git commit -m "function 1"

[master 5ec3455] function 1

 1 file changed, 5 insertions(+)

[[email protected] a]$ git log

commit 5ec3455dae0c02537c2d9ff1e001b5da97e71d9a

    function 1

git reset--soft撤銷local repo的修改

假設入庫function1以後，又有兩次commit（feature2.1、feature2.2）

[[email protected] a]$ git log -3

commit 40e8c12abff40aba66d8fa6ed4970a93890d755a

    feature 2.2

commit f0aac7525f6cb0be069662b0b3c52e8edf411a62

    feature 2.1

commit 5ec3455dae0c02537c2d9ff1e001b5da97e71d9a

    function 1

使用git reset –soft，撤銷最近的兩次commit操作

[[email protected] a]$ git reset --soft 5ec3455dae0c02537c2d9ff1e001b5da97e71d9a

 [[email protected] a]$ git log -1

commit 5ec3455dae0c02537c2d9ff1e001b5da97e71d9a

    function 1

 [[email protected] a]$ git status

# On branch master

# Changes to be committed:

#   (use "git reset HEAD <file>..." to unstage)

#

#       modified:   a.txt

#

可以看到git log已經刪除了最近兩次commit，但是status內還保留了add a.txt的操作。之後入庫只需直接commit即可。

git reset –hard撤銷本地檔案、statge、local repo的修改

git reset –hard不再贅述，其特徵是本地檔案也將恢復成指定HEAD的狀態（所做修改被丟棄），慎用！

git revert

git revert將指定commit所包含的修改回退後再commit，從而撤銷該次入庫，其順利執行的前提是涉及檔案與其他commit不存在衝突。

[[email protected] a]$ git log

commit c4b214aff15850d17b386b10cf2cd5e855f27f33

    feature 2.3

commit 7e42cf823c6efe22dee4382a847a744914572e35

    feature 2.2

commit cd342b2acc8bb7f4ca5f18900ea4526aa307618e

    feature 2.1

[[email protected] a]$ git revert 7e42cf823c6efe22dee4382a847a744914572e35

[master 04d7880] Revert "feature 2.2"

 0 files changed

 delete mode 100644 feature2.2

 [[email protected] a]$ git log

commit 04d788084fcfb3bbc79caa47350d7edd2d6e50a6

    Revert "feature 2.2"

    This reverts commit 7e42cf823c6efe22dee4382a847a744914572e35.

commit c4b214aff15850d17b386b10cf2cd5e855f27f33

    feature 2.3

commit 7e42cf823c6efe22dee4382a847a744914572e35

    feature 2.2

commit cd342b2acc8bb7f4ca5f18900ea4526aa307618e

feature 2.1

小結

git reset和git revert可以達到同樣的效果，git reset主要用於push到遠端庫之前對本地檔案和commit進行調整；git revert通過增加一次新的入庫，恢復指定入庫的修改，相對來說比較方便，但是需要避免衝突。

衝突操作

無關檔案

a在function1之後入庫了feature2.x，b在function1之後本地增加了feature3.1，此時b入庫會提示錯誤：

[[email protected] b]$ git push

To ssh://[email protected]:7999/gpon/test.git

 ! [rejected]        master -> master (non-fast-forward)

error: failed to push some refs to 'ssh://[email protected]:7999/gpon/test.git'

hint: Updates were rejected because the tip of your current branch is behind

hint: its remote counterpart. Merge the remote changes (e.g. 'git pull')

hint: before pushing again.

hint: See the 'Note about fast-forwards' in 'git push --help' for details.

此時需要重新pull 一次遠端庫，獲取到遠端庫的修改

[[email protected] b]$ git pull origin master

From ssh://sny-jira.ads.finisar.com:7999/gpon/test

 * branch            master     -> FETCH_HEAD

Merge made by the 'recursive' strategy.

 0 files changed

 create mode 100644 feature2.1

 create mode 100644 feature2.2

 create mode 100644 feature2.3

此時，可以看到log的變化（在feature 3.1之前增加了feature 2.x的commit log，之後增加了一條merge的log）

[[email protected] b]$ git log

commit 006871f55dbabe3eb2852c5011b555f4cbddcb8b

Merge: 50b4877 c4b214a

    Merge branch 'master' of ssh://sny-jira.ads.finisar.com:7999/gpon/test

commit 50b48770c13bac5b6e97088d6d071649f4d55b35

    feature 3.1

commit c4b214aff15850d17b386b10cf2cd5e855f27f33

feature 2.3

commit 7e42cf823c6efe22dee4382a847a744914572e35

    feature 2.2

commit cd342b2acc8bb7f4ca5f18900ea4526aa307618e

feature 2.1

最後再push。

從log上看，其實最後一條merge log屬於一條冗餘資訊，我們當然知道應該要merge一下，如何避免這條冗餘資訊，可以參考git reset的使用。

相同檔案

假設a在a.txt增加了feature 4.1，已入到遠端庫，b在a.txt增加feature 4.2，此時pull也會提示錯誤：

[[email protected] b]$ git pull origin master

remote: Counting objects: 5, done.

remote: Compressing objects: 100% (3/3), done.

remote: Total 3 (delta 2), reused 0 (delta 0)

Unpacking objects: 100% (3/3), done.

From ssh://sny-jira.ads.finisar.com:7999/gpon/test

 * branch            master     -> FETCH_HEAD

Auto-merging a.txt

CONFLICT (content): Merge conflict in a.txt

Automatic merge failed; fix conflicts and then commit the result.

使用git status，可以看到自動merge失敗的檔案a.txt

[[email protected] b]$ git status

# On branch master

# Unmerged paths:

#   (use "git add/rm <file>..." as appropriate to mark resolution)

#

#       both modified:      a.txt

#

no changes added to commit (use "git add" and/or "git commit -a")

使用git diff，可以檢視具體的差異，03ef4d19eb8c2ad7b93ce7e486f6a01ab7e0856d是遠端庫的commit id。

[[email protected] b]$ git diff a.txt

diff --cc a.txt

index 7e6411a,a32e92b..0000000

--- a/a.txt

+++ b/a.txt

@@@ -7,4 -7,4 +7,8 @@@ function

     feature 1.3

  function 4

++<<<<<<< HEAD

 +   feature 4.2

++=======

+    feature 4.1

根據需要修改a.txt，git add，git commit後，push。