For example, I start from a clean commit, make some changes to different files, then I want to remove changes I made from only one file. How do I do it?
I tried to do:
git stash -p train.py
But I've got the error:
fatal: subcommand wasn't specified; 'push' can't be assumed due to unexpected token 'train.py'
The reason why you're getting that error is because git stash push (which git stash -p is an alias for), doesn't allow custom arguments in order to avoid unintended stashing.
From the documentation for git stash push:
For quickly making a snapshot, you can omit "push". In this mode, non-option arguments are not allowed to prevent a misspelled subcommand from making an unwanted stash entry. The two exceptions to this are
stash -pwhich acts as alias forstash push -pand pathspec elements, which are allowed after a double hyphen--for disambiguation.
In your case, train.py is a pathspec, so you must separate it from the recognized options by adding a -- like this:
git stash -p -- train.py
Alternatively, you can spell out the entire command, in which case you don't have to separate the path with a double dash:
git stash push -p train.py
Note that using a double dash -- to clearly separate a pathspec from a command's known options is a convention used by all Git commands that accept paths.
You should:
git rebase HEAD~1
# Change, by the editor just opened, the word pick into edit, save and exit
# Edit you file
git commit