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X11 forwarding request failed on channel 0

If you run into issues with X11 Forwarding while pushing/pulling from GitHub, you can try the following:

echo $'Host\n    ForwardX11 no' >> ~/.ssh/config

This turns off X11 forwarding to ssh connections.

(H/T to Scott Chow, F19 TA for this tip)

Help! I committed changes to my local master when they should have been on a feature branch

Suppose you intended to create a feature branch called cg-myFeature and put three commits on it.

But you forgot! You put those three commits on the master branch instead! And you do NOT want to push those directly to master—instead, you want to:

  • put those commits on the gc-myFeature branch, and
  • get your local master branch back in sync with the master of the origin.


  • Because you want to do a pull request for your new commits.
  • You do not want them to just go to master directy.

What can you do?

The important thing to rememebr is what a branch is.

  • A branch is nothing more, and nothing less, than a pointer to a commit.


First, do a git status followed by a git log command at the shell prompt in your local repo.

Suppose that looks like this:

$ git status
On branch master
Your branch and 'origin/master' have diverged,
and have 2 and 4 different commits each, respectively.
  (use "git pull" to merge the remote branch into yours)
nothing to commit, working tree clean
$ git log
commit 6902efff2938412834123487129384719232ea98
Author: Chris Gaucho <>
Date:   Tue Jan 28 11:33:29 2020 -0800
    cg - added file for team questions
commit 0d066b54aacd684f11642c1881a5755e25fae037
Author: Chris Gaucho <>
Date:   Tue Jan 28 11:29:31 2020 -0800
    cg - added file for qa questions
commit fd91befce9897845d996ccdb17cebeb948529368 (origin/cg-myFeature)
Author: ldelplaya <>
Date:   Tue Jan 28 11:11:54 2020 -0800
    Initial commit

Also go to the repo on GitHub (i.e. the website, and under commits, find out what the SHA (that long hexadecimal number) is for the latest up-to-date commit on master. Suppose that number is: c547d12. (Note that the full number is longer, but you can typically shorten SHAs on GitHub to the first seven digits and it works fine.)

What we want, is to end up with the commits shown above (i.e. the last commit being 6902eff, which has the message cg - added file for team questions) to be on the branch cg-myFeature, and for our local master to be back pointing to c547d12`).

So, here’s what we do.

Command Explanation
git fetch This updates the branch pointers for all our origin/master, origin/branch, origin/branch2, etc. for all the branches that exists on origin. It doesn’t pull anything; it just makes sure our local repo knows where all the pointers are. We’ll need that later.
git checkout cg-myFeature This puts us on the feature branch
git reset --hard 6902eff This should move the feature branch point to be pointing at the last commit that we want to be on the feature branch. At this point, both master and cg-myFeature point to that last commit
git push -f origin cg-myFeature This does a “force push” on the cg-myFeature branch. This forces GitHub’s pointer for that branch to be pointing to the commit we insist on. This is something you should only do when you are pretty confident that your local branch is pointing to the correct spot, and that the branch on GitHub is not.
git status It’s a good idea to do a git status now, as well as checking things on GitHub to be sure they look sane
git checkout master Now we are going to fix our local master branch
git reset --hard origin/master This says: make the current branch (which happens to be our local master) point wherever origin/master points. That’s going to make our local branch be in sync with master.
git status You should now see the message:
On Branch Master
Your branch is up-to-date with 'origin/master'

nothing to commit, working tree clean