checkout是切换分支，这个切换仅是在本地所储存的分支分支中切换是吗？
也就是说checkout命令是不需要联网的是吗？
同事写了一个同步脚本为：
git checkout -f
git pull
我理解为：强制checkout到HEAD，然后执行pull，对吗？
checkout是本地命令
git-checkout - Checkout a branch or paths to the working tree
git 不需要联网就可以使用,你的理解是对的
git checkout -f 我测试了下，结果是这样的
rails@1hao:~/tmp/tmp$ git branch
* hello
master
rails@1hao:~/tmp/tmp$ git checkout -f
rails@1hao:~/tmp/tmp$ git branch
* hello
master
另外 git-checkout man手册里是这样说的
-f, --force
When switching branches, proceed even if the index or the working tree differs from HEAD. This is used to throw away local changes.
改了文件，加了个文件测试了下
rails@1hao:~/tmp/tmp$ git status
# On branch hello
# Changes to be committed:
# (use "git reset HEAD <file>..." to unstage)
#
# new file: b
#
# Changes not staged for commit:
# (use "git add <file>..." to update what will be committed)
# (use "git checkout -- <file>..." to discard changes in working directory)
#
# modified: a
#
# Untracked files:
# (use "git add <file>..." to include in what will be committed)
#
# c
rails@1hao:~/tmp/tmp$ git checkout -f
rails@1hao:~/tmp/tmp$ git status
# On branch hello
# Untracked files:
# (use "git add <file>..." to include in what will be committed)
#
# c
nothing added to commit but untracked files present (use "git add" to track)
那些更改的和添加到缓存区的文件都没有了