撤销 git reset --hard HEAD~1

方法一：

1.先通过git reflog找到上一次的历史提交记录id，git如果没有特意设置，是会保存记录一段时间的(a few days or a month)

2.git reset --hard [id]

方法二：

git reset --hard HEAD@{1}

直接回到刚才的那个结点，{}中表示的是结点的序号

方法一的例子如下：

$ git init

Initialized empty Git repository in .git/

$ echo "testing reset" > file1

$ git add file1

$ git commit -m 'added file1'

Created initial commit 1a75c1d: added file1

1 files changed, 1 insertions(+), 0 deletions(-)

create mode 100644 file1

$ echo "added new file" > file2

$ git add file2

$ git commit -m 'added file2'

Created commit f6e5064: added file2

1 files changed, 1 insertions(+), 0 deletions(-)

create mode 100644 file2

$ git reset --hard HEAD^

HEAD is now at 1a75c1d... added file1

$ cat file2

cat: file2: No such file or directory

$ git reflog

1a75c1d... HEAD@{0}: reset --hard HEAD^: updating HEAD

f6e5064... HEAD@{1}: commit: added file2

$ git reset --hard f6e5064

HEAD is now at f6e5064... added file2

$ cat file2

added new file