reset

• Usage: java gitlet.Main reset [commit id]
• Description: Checks out all the files tracked by the given commit. Removes tracked files that are not present in that commit. Also moves the current branch's head to that commit node. See the intro for an example of what happens to the head pointer after using reset. The [commit id] may be abbreviated as for checkout. The staging area is cleared. The command is essentially checkout of an arbitrary commit that also changes the current branch head.
• Runtime: Should be linear with respect to the total size of files tracked by the given commit's snapshot. Should be constant with respect to any measure involving number of commits.
• Failure case: If no commit with the given id exists, print No commit with that id exists. If a working file is untracked in the current branch and would be overwritten by the reset, print There is an untracked file in the way; delete it, or add and commit it first. and exit; perform this check before doing anything else.
• Dangerous?: Yes!
• Differences from real git: This command is closest to using the --hard option, as in git reset --hard [commit hash].
• Our line count: ~10