Git 简明教程
Git - Update Operation
Modify Existing Function
Tom 执行克隆操作并找到了一个新文件 string.c。他想了解是谁将此文件添加到仓库的以及出于什么目的，因此他执行了 git log 命令。
Tom performs the clone operation and finds a new file string.c. He wants to know who added this file to the repository and for what purpose, so, he executes the git log command.
[tom@CentOS ~]$ git clone gituser@git.server.com:project.git以上命令将生成以下结果 −
The above command will produce the following result −
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)克隆操作将在当前工作目录中创建一个新目录。他将目录更改为新创建的目录并执行 git log 命令。
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.
[tom@CentOS ~]$ cd project/
[tom@CentOS project]$ git log以上命令将生成以下结果 −
The above command will produce the following result −
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在观察日志后，他意识到文件 string.c 是由 Jerry 添加的，以实现基本字符串操作。他对 Jerry 的代码感到好奇。因此，他在文本编辑器中打开了 string.c，并立即发现了错误。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 −
After observing the log, he realizes that the file string.c was added by Jerry to implement basic string operations. He is curious about Jerry’s code. So he opens string.c in text editor and immediately finds a bug. In my_strlen function, Jerry is not using a constant pointer. So, he decides to modify Jerry’s code. After modification, the code looks as follows −
[tom@CentOS project]$ git diff以上命令将生成以下结果 −
The above command will produce the following result −
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;
}在测试后，他提交了他的更改。
After testing, he commits his change.
[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以上命令将生成以下结果 −
The above command will produce the following result −
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 commitTom 使用 git push 命令去推送他的更改。
Tom uses git push command to push his changes.
[tom@CentOS project]$ git push origin master以上命令将生成以下结果 −
The above command will produce the following result −
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 −> masterAdd New Function
与此同时，Jerry 决定实现 string compare 功能。因此，他修改了 string.c。修改后，该文件如下所示 −
Meanwhile, Jerry decides to implement string compare functionality. So he modifies string.c. After modification, the file looks as follows −
[jerry@CentOS project]$ git diff以上命令将生成以下结果 −
The above command will produce the following result −
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;
}
}经过测试，他准备推送自己的变更。
After testing, he is ready to push his change.
[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验证提交。
Before push operation, he verifies commit by viewing log messages.
[jerry@CentOS project]$ git log以上命令将生成以下结果 −
The above command will produce the following result −
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 commitJerry 对更改感到满意，他想推送他的更改。
Jerry is happy with the changes and he wants to push his changes.
[jerry@CentOS project]$ git push origin master以上命令将生成以下结果 −
The above command will produce the following result −
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 Jerry 推送他的更改。因为 Git 识别出远程仓库和 Jerry 的本地仓库不同步。因此，他可能会丢失项目的历史记录。为了避免出现混乱，Git 失败了此操作。现在，Jerry 必须首先更新本地仓库，然后才能推送自己的更改。
But Git is not allowing Jerry to push his changes. Because Git identified that remote repository and Jerry’s local repository are not in sync. Because of this, he can lose the history of the project. To avoid this mess, Git failed this operation. Now, Jerry has to first update the local repository and only thereafter, he can push his own changes.
Fetch Latest Changes
Jerry 执行 git pull 命令将他的本地仓库与远程仓库同步。
Jerry executes the git pull command to synchronize his local repository with the remote one.
[jerry@CentOS project]$ git pull以上命令将生成以下结果 −
The above command will produce the following result −
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在 pull 操作之后，Jerry 检查日志消息并查找 Tom 的提交的详细信息，提交 ID 为 cea2c000f53ba99508c5959e3e12fff493ba6f69
After pull operation, Jerry checks the log messages and finds the details of Tom’s commit with commit ID cea2c000f53ba99508c5959e3e12fff493ba6f69
[jerry@CentOS project]$ git log以上命令将生成以下结果 −
The above command will produce the following result −
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 的本地仓库已与远程仓库完全同步。因此，他可以安全地推送自己的更改。
Now, Jerry’s local repository is fully synchronized with the remote repository. So he can safely push his changes.
[jerry@CentOS project]$ git push origin master以上命令将生成以下结果 −
The above command will produce the following result −
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