为了浏览你的修改，可以使用 svn status 命令。在所有的 Subversion 命令中，svn status 可能会是你使用最多的命令。

如果你在工作副本的顶级目录运行不带参数的 svn status 命令，它会检测你对所有文件或目录作出的修改。以下的例子是来展示 svn status 可能返回的状态代码(注意 # 之后的内容不是 svn status 打印的信息)。

?       scratch.c           # file is not under version control
A       stuff/loot/bloo.h   # file is scheduled for addition
C       stuff/loot/lump.c   # file has textual conflicts from an update
D       stuff/fish.c        # file is scheduled for deletion
M       bar.c               # the content in bar.c has local modifications

在这种输出格式中，svn status 打印 6 列字符，紧跟一些空格，接着是文件或目录名。第一列告诉文件或目录的状态或它的内容。返回代码如下：

如果你传递一个路径给svn status，它只给你这个项目的信息：

$ svn status stuff/fish.c
D      stuff/fish.c

svn status也有一个--verbose(-v)选项，它可以显示工作副本中的所有项目，即使没有改变过的：

$ svn status -v
M               44        23    sally     README
                44        30    sally     INSTALL
M               44        20    harry     bar.c
                44        18    ira       stuff
                44        35    harry     stuff/trout.c
D               44        19    ira       stuff/fish.c
                44        21    sally     stuff/things
A                0         ?     ?        stuff/things/bloo.h
                44        36    harry     stuff/things/gloo.c

这是 svn status 的“长形式”。第一列的含义不变，第二列显示工作版本号。第三列和第四列显示最后一次修改的版本号和修改者。

上面所有的 svn status调用并没有联系版本库—只是与 .svn 中的原始数据进行比较。最后，使用 --show-updates(-u) 选项，它将会联系版本库，为已经过时的数据增加新信息：

$ svn status -u -v
M      *        44        23    sally     README
M               44        20    harry     bar.c
       *        44        35    harry     stuff/trout.c
D               44        19    ira       stuff/fish.c
A                0         ?     ?        stuff/things/bloo.h
Status against revision:   46

注意这两个星号：如果你现在执行 svn update，你的 README 和 trout.c 会被更新。这告诉你许多有用的信息—你需要在提交之前，使用更新操作得到服务器中文件 README 的更新，否则服务器会说文件已经过时，拒绝你的提交(后面还有更多关于此主题的信息)。

svn status 可以比我们的展示显示更多关于文件和目录的内容—svn status 的完整描述可以参见svn status。

另一种检查修改的方式是 svn diff 命令。你可以通过不带参数的 svn diff 精确的找出你所做的修改，它会输出统一差异格式的修改信息：

$ svn diff
Index: bar.c
===================================================================
--- bar.c	(revision 3)
+++ bar.c	(working copy)
@@ -1,7 +1,12 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <stdio.h>

 int main(void) {
-  printf("Sixty-four slices of American Cheese...\n");
+  printf("Sixty-five slices of American Cheese...\n");
 return 0;
 }

Index: README
===================================================================
--- README	(revision 3)
+++ README	(working copy)
@@ -193,3 +193,4 @@
+Note to self:  pick up laundry.

Index: stuff/fish.c
===================================================================
--- stuff/fish.c	(revision 1)
+++ stuff/fish.c	(working copy)
-Welcome to the file known as 'fish'.
-Information on fish will be here soon.

Index: stuff/things/bloo.h
===================================================================
--- stuff/things/bloo.h	(revision 8)
+++ stuff/things/bloo.h	(working copy)
+Here is a new file to describe
+things about bloo.

svn diff 命令通过比较你的文件与存储在 .svn 的“原始”文件来输出信息，预定要增加的文件会显示所有增加的文本，预定要删除的文件会显示所有要删除的文本。

输出的格式为统一差异格式。删除的行前面加一个 -，增加的行前面有一个 +。svn diff 命令也打印文件名和补丁程序需要的位置信息，所以你可以通过重定向一个差异文件来生成“补丁”：

$ svn diff > patchfile

举个例子，你可以通过邮件把补丁文件发送到其他开发者，在提交之前审核或测试。

Subversion 使用内置差异引擎，默认输出统一差异格式。如果你期望不同的输出格式，你可以使用 --diff-cmd 指定外置的比较程序，并且通过选项 --extensions (-x) 来传递其它参数。例如，察看本地文件 foo.c 的本地修改，同时忽略大小写差异，你可以运行 svn diff --diff-cmd /usr/bin/diff -x "-i" foo.c。

$ svn update
U  INSTALL
G  README
Conflict discovered in 'bar.c'.
Select: (p) postpone, (df) diff-full, (e) edit,
        (h) help for more options:

…
  (p)  postpone    - mark the conflict to be resolved later
  (df) diff-full   - show all changes made to merged file
  (e)  edit        - change merged file in an editor
  (r)  resolved    - accept merged version of file
  (mf) mine-full   - accept my version of entire file (ignore their changes)
  (tf) theirs-full - accept their version of entire file (lose my changes)
  (l)  launch      - launch external tool to resolve conflict
  (h)  help        - show this list

Before deciding how to attack a conflict interactively, odds are that you'd like to see exactly what is in conflict, and the diff-full command (df) is what you'll use for this:

…
Select: (p) postpone, (df) diff-full, (e) edit,
        (h)elp for more options : df
--- .svn/text-base/sandwich.txt.svn-base      Tue Dec 11 21:33:57 2007
+++ .svn/tmp/tempfile.32.tmp     Tue Dec 11 21:34:33 2007
@@ -1 +1,5 @@
-Just buy a sandwich.
+<<<<<<< .mine
+Go pick up a cheesesteak.
+=======
+Bring me a taco!
+>>>>>>> .r32
…

The first line of the diff content shows the previous contents of the working copy (the BASE revision), the next content line is your change, and the last content line is the change that was just received from the server (usually the HEAD revision). With this information in hand, you're ready to move on to the next action.

There are four different ways to resolve conflicts interactively—two of which allow you to selectively merge and edit changes, and two of which allow you to simply pick a version of the file and move along.

If you wish to choose some combination of your local changes, you can use the “edit” command (e) to manually edit the file with conflict markers in a text editor (determined by the EDITOR environment variable). Editing the file by hand in your favorite text editor is a somewhat low-tech way of remedying conflicts (see 第 4.5.4 节 “手工合并冲突” for a walkthrough), so some people like to use fancy graphical merge tools instead.

To use a merge tool, you need to either set the SVN_MERGE environment variable or define the merge-tool-cmd option in your Subversion configuration file (see 第 1.3 节 “配置选项” for more details). Subversion will pass four arguments to the merge tool: the BASE revision of the file, the revision of the file received from the server as part of the update, the copy of the file containing your local edits, and the merged copy of the file (which contains conflict markers). If your merge tool is expecting arguments in a different order or format, you'll need to write a wrapper script for Subversion to invoke. After you've edited the file, if you're satisfied with the changes you've made, you can tell Subversion that the edited file is no longer in conflict by using the “resolve” command (r).

If you decide that you don't need to merge any changes, but just want to accept one version of the file or the other, you can either choose your changes (a.k.a. “mine”) by using the “mine-full” command (mf) or choose theirs by using the “theirs-full” command (tf).

This may sound like an appropriate section for avoiding marital disagreements, but it's actually still about Subversion, so read on. If you're doing an update and encounter a conflict that you're not prepared to review or resolve, you can type p to postpone resolving a conflict on a file-by-file basis when you run svn update. If you're running an update and don't want to resolve any conflicts, you can pass the --non-interactive option to svn update, and any file in conflict will be marked with a C automatically.

The C stands for conflict. This means that the changes from the server overlapped with your own, and now you have to manually choose between them after the update has completed. When you postpone a conflict resolution, svn typically does three things to assist you in noticing and resolving that conflict:

For example, Sally makes changes to the file sandwich.txt, but does not yet commit those changes. Meanwhile, Harry commits changes to that same file. Sally updates her working copy before committing and she gets a conflict, which she postpones:

$ svn update
Conflict discovered in 'sandwich.txt'.
Select: (p) postpone, (df) diff-full, (e) edit,
        (h)elp for more options : p
C  sandwich.txt
Updated to revision 2.
$ ls -1
sandwich.txt
sandwich.txt.mine
sandwich.txt.r1
sandwich.txt.r2

At this point, Subversion will not allow Sally to commit the file sandwich.txt until the three temporary files are removed:

$ svn commit -m "Add a few more things"
svn: Commit failed (details follow):
svn: Aborting commit: '/home/sally/svn-work/sandwich.txt' remains in conflict

If you've postponed a conflict, you need to resolve the conflict before Subversion will allow you to commit your changes. You'll do this with the svn resolve command and one of several arguments to the --accept option.

如果你希望选择上次检出后修改之前的文件版本，选择base参数。

如果你希望选择只包含你修改的版本，选择mine-full参数。

如果你希望选择最近从服务器更新的版本(因此会丢弃你的所以编辑)，选择theirs-full参数。

However, if you want to pick and choose from your changes and the changes that your update fetched from the server, merge the conflicted text “by hand” (by examining and editing the conflict markers within the file) and then choose the working argument.

svn resolve removes the three temporary files and accepts the version of the file that you specified with the --accept option, and Subversion no longer considers the file to be in a state of conflict:

$ svn resolve --accept working sandwich.txt
Resolved conflicted state of 'sandwich.txt'

第一次尝试解决冲突让人感觉很害怕，但经过一点训练，它简单的像是骑着车子下坡。

Here's an example. Due to a miscommunication, you and Sally, your collaborator, both edit the file sandwich.txt at the same time. Sally commits her changes, and when you go to update your working copy, you get a conflict and you're going to have to edit sandwich.txt to resolve the conflict. First, let's take a look at the file:

$ cat sandwich.txt
Top piece of bread
Mayonnaise
Lettuce
Tomato
Provolone
<<<<<<< .mine
Salami
Mortadella
Prosciutto
=======
Sauerkraut
Grilled Chicken
>>>>>>> .r2
Creole Mustard
Bottom piece of bread

The strings of less-than signs, equals signs, and greater-than signs are conflict markers and are not part of the actual data in conflict. You generally want to ensure that those are removed from the file before your next commit. The text between the first two sets of markers is composed of the changes you made in the conflicting area:

<<<<<<< .mine
Salami
Mortadella
Prosciutto
=======

后两组之间的是Sally提交的修改冲突：

=======
Sauerkraut
Grilled Chicken
>>>>>>> .r2

Usually you won't want to just delete the conflict markers and Sally's changes—she's going to be awfully surprised when the sandwich arrives and it's not what she wanted. This is where you pick up the phone or walk across the office and explain to Sally that you can't get sauerkraut from an Italian deli. ^[5] Once you've agreed on the changes you will commit, edit your file and remove the conflict markers:

Top piece of bread
Mayonnaise
Lettuce
Tomato
Provolone
Salami
Mortadella
Prosciutto
Creole Mustard
Bottom piece of bread

Now use svn resolve, and you're ready to commit your changes:

$ svn resolve --accept working sandwich.txt
Resolved conflicted state of 'sandwich.txt'
$ svn commit -m "Go ahead and use my sandwich, discarding Sally's edits."

Note that svn resolve, unlike most of the other commands we deal with in this chapter, requires that you explicitly list any filenames that you wish to resolve. In any case, you want to be careful and use svn resolve only when you're certain that you've fixed the conflict in your file—once the temporary files are removed, Subversion will let you commit the file even if it still contains conflict markers.

If you ever get confused while editing the conflicted file, you can always consult the three files that Subversion creates for you in your working copy—including your file as it was before you updated. You can even use a third-party interactive merging tool to examine those three files.

If you get a conflict and decide that you want to throw out your changes, you can run svn resolve --accept theirs-full CONFLICTED-PATH and Subversion will discard your edits and remove the temporary files:

$ svn update
Conflict discovered in 'sandwich.txt'.
Select: (p) postpone, (df) diff-full, (e) edit,
        (h) help for more options: p
C    sandwich.txt
Updated to revision 2.
$ ls sandwich.*
sandwich.txt  sandwich.txt.mine  sandwich.txt.r2  sandwich.txt.r1
$ svn resolve --accept theirs-full sandwich.txt
Resolved conflicted state of 'sandwich.txt'

If you decide that you want to throw out your changes and start your edits again (whether this occurs after a conflict or anytime), just revert your changes:

$ svn revert sandwich.txt
Reverted 'sandwich.txt'
$ ls sandwich.*
sandwich.txt

Note that when you revert a conflicted file, you don't have to use svn resolve.