git diff branch_2..branch_1

fatal: ambiguous argument 'branch_2..branch_1': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'

git branch -a
* branch_1
master/origin
remotes/origin/HEAD -> origin/master
remotes/origin/branch_2
remotes/origin/branch_1

git diff branch2..branch1

git diff origin/branch2..branch1

git diff branch2..branch1

git checkout branch2

git diff branch2..branch1

git clone --depth 1 <repo-url>

fatal: ambiguous argument [...]: unknown revision or path not in the working tree.

git diff branch1