git rebase fatal: Needed a single revision invalid upstream –i

I am trying to squanshing several commits together. When I used

git rebase –i HEAD~8

I got a fatal:

fatal: Needed a single revision
invalid upstream –i

Here is a part of commit logs: git log

All of the commits history of the corresponding Github repository is here: https://github.com/yikouniao/YukiLog/commits/master

Edit1:

When I used git rebase –i HEAD~2, I got the same result.

Edit2:

I didn't know I had modified the file.gitconfig, editor = notepad2 was add to the file. After I removed editor = notepad2, everything is OK. Then I rebased and squanshed 8 commits successfully.

Several options:

• You are not on a branch (Detached head) or maybe you are trying to rebase or the wrong branch.
  Checkout the branch you want to rebase and try again.

• you don't have 8 commits in your history (you have 7 or less)

• try: git rebase -i --root

Here is the documentation for the --root flag and why it will work for you.

--root

Rebase all commits reachable from <branch>, instead of limiting them with
an <upstream>.This allows you to rebase the root commit(s) on a branch.  
When used with --onto, it will skip changes already contained in `<newbase>`   
(instead of `<upstream>`) whereas without --onto it will operate on every 
change. When used together with both --onto and --preserve-merges, all root 
commits will be rewritten to have `<newbase>` as parent instead.`

The problem is the dash in your –i. It's an en-dash (U2013) instead of a hyphen (U002D). I confirmed this by copying your dash and looking it up at http://unicode.scarfboy.com. Change it to -i instead.

The clue was the error message "invalid upstream –i". Git didn't recognize your –i as a flag and was instead interpreting it as the upstream parameter.