Setup Instructions

To Set Up Your Athena Workspace for 6.170

Log in to Athena and bring up a terminal. To do it remotely, SSH to athena.dialup.mit.edu. See IS&T Remote Athena Help if you're having trouble.

To set up your repository for 6.170, run the command:

python /afs/csail.mit.edu/proj/courses/6.170/repos/create_repo.py

Once your repository is all set up on our end, you can get things ready on your workstation. If you have windows, you'll need to install Git first, and then use the git terminal to do the upcoming commands. Otherwise use the standard system terminal.
In a terminal, navigate to wherever you want your code to be stored (say, on your laptop under Classes/6.170/, or on athena, or both, or wherever!). Then, run the following commands, being sure to replace MY_USERNAME with your athena username:
```
git clone ssh://MY_USERNAME@athena.dialup.mit.edu/afs/csail.mit.edu/proj/courses/6.170/repos/MY_USERNAME.git 6170_code
cd 6170_code
git remote add handoutcode ssh://MY_USERNAME@athena.dialup.mit.edu/afs/csail.mit.edu/proj/courses/6.170/repos/handoutcode.git
git checkout dev
git pull handoutcode master
```
You should be prompted for a password twice, once after the first command ("git clone") and once after the last command ("git pull"), where you'll have to enter your athena password. As a check to make sure you can submit your code, go ahead and add a special message in the README file and then run
```
git push origin dev:submit
```

To Complete an Assignment

Go into terminal and navigate to wherever you cloned your repository and run:
```
git pull handoutcode master
```
to make sure you have the most up to date handout code for the assignment. Be sure that you're in your "dev" branch when you pull.
You can now start working on the assignment. The work for Assignment 1 will go in the folder "assignment1", the work for Assignment 2 in "assignment2" etc.; these folders should already have been created for you if you pulled the handed-out code correctly.
While your work progresses, you can make commits to your working repository. See the git reference below for how to do this. Remember, however, that these commits are only local to your computer. To back them up to the server, run
```
git push
```
When your work is in such a state that you wish to submit it, issue the following command:
```
git push origin dev:submit
```
You can do this as many times as you want before the deadline for each assignment. We will fetch the last commit before the deadline for grading. (Still, we don't guarantee that we won't use a slightly later commit, so don't push a commit that breaks your code right after the deadline either). Note that you might get your repository into a weird state where it complains about the push not being a "fast-forward" commit, or similar. In this case, you have to force git to comply by using
```
git push origin +dev:submit
```

Git Reference

Once a git repository is set up and you have CDed into it's directory, these are the most frequently used git commands:

```
git status
```
Used all the time, to see a list of files changed since the last commit, and which of these changes are staged for inclusion in the next commit.
```
git diff <file>
```
See the changes you have made to files or a particular file since the last commit. Typically you run "git diff" for each file with unstaged changes to review your changes before adding it with "git add", then finally when you have reviewed all files you do "git commit".
```
git add <file>
```
Used to stage the changes in a modified file for inclusion in the next commit, or to add a file that has never been checked in before so that it is included on the next commit.
```
git reset <file>
```
The opposite of "git add"--the changes to this file will not be included in the next commit after all (unless the file is added with "git add" again).
```
git checkout <file>
```
Revert the changes made to the specified file, replacing it with the latest version from the repository. Similar to SVN's "revert". Warning: this will erase you changes to that file! Note: The same command is also used to switch between branches.
```
git commit -m "Commit message."
```
Commit the changes you staged with "git add" to the current branch (often the "master" branch is the only one) of your local repository.
```
git log
```
Shows all the commits in your local repository (to this branch), with their commit messages and authors.
```
git branch -a
```
Shows all the branches in the repository, both local and remote, with an astrick denoting the current branch
```
git checkout <branch>
```
Switch to the specified branch.
```
git pull
```
Retrieve (and merge) the latest updates from the remote repository from which the local repository was cloned.
```
git push
```
Push the latest series of commits from the current repository to the remote repository from which it was cloned.