Merge pull request #183 from networm/09-git-and-other-scms_import-tfs

Translate 09-git-and-other-scms import-tfs

Author: networm

book/09-git-and-other-scms/sections/import-tfs.asc

@@ -2,59 +2,59 @@
 ==== TFS
 
 (((TFS)))(((Importing, from TFS)))
-If your team is converting their source control from TFVC to Git, you'll want the highest-fidelity conversion you can get.
-This means that, while we covered both git-tfs and git-tf for the interop section, we'll only be covering git-tfs for this part, because git-tfs supports branches, and this is prohibitively difficult using git-tf.
+如果你的团队正在将他们的源代码管理从 TFVC 转换为 Git，你们会想要最高程度的无损转换。
+这意味着，虽然我们在之前的交互章节介绍了 git-tfs 与 git-tf 两种工具，但是我们在本部分只能介绍 git-tfs，因为 git-tfs 支持分支，而使用 git-tf 代价太大。
 
 [NOTE]
 ====
-This is a one-way conversion.
-The resulting Git repository won't be able to connect with the original TFVC project.
+这是一个单向转换。
+这意味着 Git 仓库无法连接到原始的 TFVC 项目。
 ====
 
-The first thing to do is map usernames.
-TFVC is fairly liberal with what goes into the author field for changesets, but Git wants a human-readable name and email address.
-You can get this information from the `tf` command-line client, like so:
+第一件事是映射用户名。
+TFVC 对待变更集作者字段的内容相当宽容，但是 Git 需要人类可读的名字与邮箱地址。
+可以通过 `tf` 命令行客户端来获取这个信息，像这样：
 
 [source,powershell]
 ----
 PS> tf history $/myproject -recursive > AUTHORS_TMP
 ----
 
-This grabs all of the changesets in the history of the project and put it in the AUTHORS_TMP file that we will process to extract the data of the 'User' column (the 2nd one).
-Open the file and find at which characters start and end the column and replace, in the following command-line, the parameters `11-20` of the `cut` command with the ones found:
+这会将历史中的所有变更集抓取下来并放到 AUTHORS_TMP 文件中，然后我们将会将 `User` 列（第二个）取出来。
+打开文件找到列开始与结束的字符并替换，在下面的命令行中，`cut` 命令的参数 `11-20` 就是我们找到的：
 
 [source,powershell]
 ----
 PS> cat AUTHORS_TMP | cut -b 11-20 | tail -n+3 | uniq | sort > AUTHORS
 ----
 
-The `cut` command keeps only the characters between 11 and 20 from each line.
-The `tail` command skips the first two lines, which are field headers and ASCII-art underlines.
-The result of all of this is piped to `uniq` to eliminate duplicates, and saved to a file named `AUTHORS`.
-The next step is manual; in order for git-tfs to make effective use of this file, each line must be in this format:
+`cut` 命令只会保留每行中第 11 个到第 22 个字符。
+`tail` 命令会跳过前两行，就是字段表头与 ASCII 风格的下划线。
+所有这些的结果通过管道送到 `uniq` 来去除重复，然后保存到 `AUTOHRS` 文件中。
+下一步是手动的；为了让 git-tfs 有效地使用这个文件，每一行必须是这种格式：
 
 [source,text]
 ----
 DOMAIN\username = User Name <[email protected]>
 ----
 
-The portion on the left is the ``User'' field from TFVC, and the portion on the right side of the equals sign is the user name that will be used for Git commits.
+左边的部分是 TFVC 中的 ``User'' 字段，等号右边的部分是将被用作 Git 提交的用户名。
 
-Once you have this file, the next thing to do is make a full clone of the TFVC project you're interested in:
+一旦有了这个文件，下一件事就是生成一个你需要的 TFVC 项目的完整克隆：
 
 [source,powershell]
 ----
 PS> git tfs clone --with-branches --authors=AUTHORS https://username.visualstudio.com/DefaultCollection $/project/Trunk project_git
 ----
 
-Next you'll want to clean the `git-tfs-id` sections from the bottom of the commit messages.
-The following command will do that:
+接下来要从提交信息底部清理 `git-tfs-id` 区块。
+下面的命令会完成这个任务：
 
 [source,powershell]
 ----
 PS> git filter-branch -f --msg-filter 'sed "s/^git-tfs-id:.*$//g"' -- --all
 ----
 
-That uses the `sed` command from the Git-bash environment to replace any line starting with ``git-tfs-id:'' with emptiness, which Git will then ignore.
+那会使用 Git 终端环境中的 `sed` 命令来将所有以 ``git-tfs-id:'' 开头的行替换为 Git 会忽略的空白。
 
-Once that's all done, you're ready to add a new remote, push all your branches up, and have your team start working from Git.
+全部完成后，你就已经准备好去增加一个新的远程仓库，推送你所有的分支上去，然后你的团队就可以开始用 Git 工作了。