修改現有功能

Tom 執行克隆操作并找到一個新文件 string.c。他想知道誰將此文件添加到存儲庫中以及出于什么目的，因此，他執行了git log命令。

[tom@CentOS ~]$ git clone gituser@git.server.com:project.git

上述命令將產生以下結果

Initialized empty Git repository in /home/tom/project/.git/
remote: Counting objects: 6, done.
remote: Compressing objects: 100% (4/4), done.
Receiving objects: 100% (6/6), 726 bytes, done.
remote: Total 6 (delta 0), reused 0 (delta 0)

克隆操作將在當前工作目錄中創建一個新目錄。他將目錄更改為新創建的目錄并執行git log命令。

[tom@CentOS ~]$ cd project/
[tom@CentOS project]$ git log

上述命令將產生以下結果

commit d1e19d316224cddc437e3ed34ec3c931ad803958
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:05:26 2013 +0530
Changed return type of my_strlen to size_t
commit 19ae20683fc460db7d127cf201a1429523b0e319
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 07:32:56 2013 +0530
Initial commit

觀察日志后，他意識到文件string.c是Jerry添加的，用于實現基本的字符串操作。他對 Jerry 的代碼很好奇。于是他在文本編輯器中打開 string.c 并立即發現了一個錯誤。在 my_strlen 函數中，Jerry 沒有使用常量指針。因此，他決定修改 Jerry 的代碼。修改后，代碼如下

[tom@CentOS project]$ git diff

上述命令將產生以下結果

diff --git a/string.c b/string.c
index 7da2992..32489eb 100644
--- a/string.c
+++ b/string.c
@@ -1,8 +1,8 @@
#include <stdio.h>
-size_t my_strlen(char *s)
+size_t my_strlen(const char *s)
{
   - char *p = s;
   + const char *p = s;
   while (*p)
   ++p;
}

經過測試，他提交了他的更改。

[tom@CentOS project]$ git status -s
M string.c
?? string
[tom@CentOS project]$ git add string.c
[tom@CentOS project]$ git commit -m 'Changed char pointer to const char pointer'
[master cea2c00] Changed char pointer to const char pointer
1 files changed, 2 insertions(+), 2 deletions(-)
[tom@CentOS project]$ git log

上述命令將產生以下結果

commit cea2c000f53ba99508c5959e3e12fff493b
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 08:32:07 2013 +0530
Changed char pointer to const char pointer
commit d1e19d316224cddc437e3ed34ec3c931ad803958
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:05:26 2013 +0530
Changed return type of my_strlen to size_t
commit 19ae20683fc460db7d127cf201a1429523b0e319
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 07:32:56 2013 +0530
Initial commit

Tom 使用 git push 命令推送他的更改。

[tom@CentOS project]$ git push origin master

上述命令將產生以下結果

Counting objects: 5, done.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 336 bytes, done.
Total 3 (delta 1), reused 0 (delta 0)
To gituser@git.server.com:project.git
d1e19d3..cea2c00 master ?> master

添加新功能

同時，Jerry 決定實現字符串比較功能。于是他修改了string.c。修改后，文件如下所示

[jerry@CentOS project]$ git diff

上述命令將產生以下結果

index 7da2992..bc864ed 100644
--- a/string.c
+++ b/string.c
30Git Tutorials
@@ -9,9 +9,20 @@ size_t my_strlen(char *s)
return (p -s );
}
+char *my_strcpy(char *t, char *s)
+
{
   +
   char *p = t;
   +
   + while (*t++ = *s++)
   + ;
   +
   +
   return p;
   +
}
+
int main(void)
{
   int i; 
   +
   char p1[32];
   char *s[] = 
   {
      "Git tutorials",
      "Tutorials Point"
      @@ -20,5 +31,7 @@ int main(void)
      for (i = 0; i < 2; ++i)
      printf("string lenght of %s = %lu\n", s[i], my_strlen(s[i]));
      +
      printf("%s\n", my_strcpy(p1, "Hello, World !!!"));
      +
      return 0;
   }
}

在測試之后，他準備好推動他的改變。

[jerry@CentOS project]$ git status -s
M string.c
?? string
[jerry@CentOS project]$ git add string.c
[jerry@CentOS project]$ git commit -m "Added my_strcpy function"
[master e944e5a] Added my_strcpy function
1 files changed, 13 insertions(+), 0 deletions(-)

在推送操作之前，他通過查看日志消息來驗證提交。

[jerry@CentOS project]$ git log

上述命令將產生以下結果

commit e944e5aab74b26e7447d3281b225309e4e59efcd
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:41:42 2013 +0530
Added my_strcpy function
commit d1e19d316224cddc437e3ed34ec3c931ad803958
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:05:26 2013 +0530
Changed return type of my_strlen to size_t
commit 19ae20683fc460db7d127cf201a1429523b0e319
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 07:32:56 2013 +0530
Initial commit

Jerry 對這些變化很滿意，他想推動他的變化。

[jerry@CentOS project]$ git push origin master

上述命令將產生以下結果

To gituser@git.server.com:project.git
! [rejected]
master ?> master (non-fast-forward)
error: failed to push some refs to 'gituser@git.server.com:project.git'
To prevent you from losing history, non-fast-forward updates were rejected
Merge the remote changes before pushing again. See the 'Note about
fast-forwards' section of 'git push --help' for details.

但是 Git 不允許 Jerry 推送他的更改。因為 Git 發現遠程倉庫和 Jerry 的本地倉庫不同步。正因為如此，他可能會丟失項目的歷史記錄。為了避免這種混亂，Git 失敗了這個操作。現在，Jerry 必須先更新本地存儲庫，然后才能推送自己的更改。

獲取最新更改

Jerry 執行 git pull 命令以將他的本地存儲庫與遠程存儲庫同步。

[jerry@CentOS project]$ git pull

上述命令將產生以下結果

remote: Counting objects: 5, done.
remote: Compressing objects: 100% (3/3), done.
remote: Total 3 (delta 1), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
From git.server.com:project
d1e19d3..cea2c00 master ?> origin/master
First, rewinding head to replay your work on top of it...
Applying: Added my_strcpy function

拉操作后，Jerry 檢查日志消息并找到 Tom 提交 ID 為cea2c000f53ba99508c5959e3e12fff493ba6f69的提交的詳細信息

[jerry@CentOS project]$ git log

上述命令將產生以下結果

commit e86f0621c2a3f68190bba633a9fe6c57c94f8e4f
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:41:42 2013 +0530
Added my_strcpy function
commit cea2c000f53ba99508c5959e3e12fff493ba6f69
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 08:32:07 2013 +0530
Changed char pointer to const char pointer
commit d1e19d316224cddc437e3ed34ec3c931ad803958
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:05:26 2013 +0530
Changed return type of my_strlen to size_t
commit 19ae20683fc460db7d127cf201a1429523b0e319
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 07:32:56 2013 +0530
Initial commit

現在，Jerry 的本地存儲庫與遠程存儲庫完全同步。所以他可以安全地推送他的更改。

[jerry@CentOS project]$ git push origin master

上述命令將產生以下結果

Counting objects: 5, done.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 455 bytes, done.
Total 3 (delta 1), reused 0 (delta 0)
To gituser@git.server.com:project.git
cea2c00..e86f062 master ?> master

以上就是關于“Git更新操作的方法”介紹，大家如果想了解更多相關知識，不妨來關注一下動力節點的Java在線學習，里面還有更豐富的知識在等著大家去學習，希望對大家能夠有所幫助。