Git 更新操作
Git 更新操作
修改已存在的函数
Tom执行克隆操作,并找到一个新的文件string.c。他想知道是谁出于什么目的将这个文件添加到存储库中,所以他执行了git log命令。
[tom@CentOS ~]$ git clone gituser@git.server.com:project.git
上述操作将产生如下输出:
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) The Clone operation will create a new directory inside the current working directory. He changes the directory to newly created directory and executes the git log command.
克隆操作将在当前工作目录中创建一个新目录。他将当前目录更改为新创建的目录,并执行git log命令。
[tom@CentOS ~]$ cd project/ [tom@CentOS project]$ git log
上述操作将产生如下输出:
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
观察日志后,他意识到Jerry添加了文件string.c来实现基本的字符串操作。他对Jerry的代码很好奇,所以他在文本编辑器中打开了string.c,并立即发现了一个错误。在my_strlen函数中,Jerry没有使用常量指针。所以,他决定修改Jerry的代码。修改后,代码如下所示:
[tom@CentOS project]$ git diff
上述操作将产生如下输出:
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; }
进行测试后,他提交了修改后的代码。
[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
上述操作将产生如下输出:
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命令来推送他的更改。
[tom@CentOS project]$ git push origin master
上述操作将产生如下输出:
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
添加新的函数
与此同时,Jerry决定实现字符串比较功能,所以他修改了string.c.,修改后,文件如下所示:
[jerry@CentOS project]$ git diff
上述操作将产生如下输出:
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; } }
进行测试后,他准备提交修改后的代码。
[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,他通过查看日志消息来验证提交。
[jerry@CentOS project]$ git log
上述操作将产生如下输出:
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对这些变化很满意,他想推送他的修改。
[jerry@CentOS project]$ git push origin master
上述操作将产生如下输出:
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不允许Jerrry推送他的修改。因为Git发现远程存储库和Jerry的本地存储库不同步。正因为如此,他可能会失去这个项目的历史。为了避免这种混乱,Git这次操作失败了。现在,Jerry必须首先更新本地存储库,才能推送自己的版本。
获取最新版本
Jerry执行git pull命令来同步他的本地存储库和远程存储库。
[jerry@CentOS project]$ git pull
上述操作将产生如下输出:
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
拉取操作结束后,Jerry检查日志消息,找到Tom提交的ID为cea2c000f53ba99508c5959e3e12fff493ba6f69的细节。
[jerry@CentOS project]$ git log
上述操作将产生如下输出:
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
现在,Jerry的本地存储库与远程存储库完全同步。这样他就可以安全地推送他的版本。
[jerry@CentOS project]$ git push origin master
上述操作将产生如下输出:
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