4.3 仅检查更新

### 4.3 仅检查更新
如果您只想检查更新而没有实际进行更新，则可以使用特殊选项来调用Git（请参见列表12和13）。在这种情况下，Git仅检查仓库并显示其发现的结果，而不会实际进行任何更改。负责此操作的选项是--dry-run。注意，这里调用了git fetch而不是git pull。*git pull调用git fetch下载远程文件，然后调用git merge将检索到的文件与本地文件合并。因此，检查更新实际上是通过git fetch完成的。*
```
user@host :∼$ cd OpenFOAM / OpenFOAM -2.0. x/
user@host :∼/ OpenFOAM / OpenFOAM -2.0. x$ git fetch --dry - run -v
remote : Counting objects : 189 , done .
remote : Compressing objects : 100% (57/57) , done .
remote : Total 120 ( delta 89) , reused 93 ( delta 62)
Receiving objects : 100% (120/120) , 17.05 KiB , done .
Resolving deltas : 100% (89/89) , completed with 56 local objects .
From git :// github . com / OpenFOAM / OpenFOAM -2.0. x
5 ae2802 ..97 cf67d master -> origin / master
user@host :∼/ OpenFOAM / OpenFOAM -2.0. x$
```
列表 12: 仅检查更新–可用更新
```
user@host :∼$ cd OpenFOAM / OpenFOAM -2.1. x/
user@host :∼/ OpenFOAM / OpenFOAM -2.1. x$ git fetch --dry - run -v
From git :// github . com / OpenFOAM / OpenFOAM -2.1. x
= [ up to date ] master -> origin / master
user@host :∼/ OpenFOAM / OpenFOAM -2.1. x$
```
列表 13: 仅检查更新–最新