Example
You have started an interactive rebase. In the editor where you pick your commits, you decide that something is going wrong (for example a commit is missing, or you chose the wrong rebase destination), and you want to abort the rebase.
To do this, simply delete all commits and actions (i.e. all lines not starting with the # sign) and the rebase will be aborted!
The help text in the editor actually provides this hint:
# Rebase 36d15de..612f2f7 onto 36d15de (3 command(s))
#
# Commands:
# p, pick = use commit
# r, reword = use commit, but edit the commit message
# e, edit = use commit, but stop for amending
# s, squash = use commit, but meld into previous commit
# f, fixup = like "squash", but discard this commit's log message
# x, exec = run command (the rest of the line) using shell
#
# These lines can be re-ordered; they are executed from top to bottom.
#
# If you remove a line here THAT COMMIT WILL BE LOST.
#
# However, if you remove everything, the rebase will be aborted.
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
# Note that empty commits are commented out
