I am not able to push on git?

git push origin master shows an error

failed to push some refs to 'git@github.com:xyz/abc.git' To preven开发者_如何学Got you from losing history, non-fast-forward updates were rejected Merge the remote changes before pushing again. See the 'Note about fast-forwards' section of 'git push --help' for details.

What is this? How to recover this?

See the "pushing a branch" section from GitHub help page:

Dealing with “non-fast-forward” errors

From time to time you may encounter this error while pushing:

$ git push origin master
To ../remote/
 ! [rejected]        master -> master (non-fast forward)
error: failed to push some refs to '../remote/'
To prevent you from losing history, non-fast-forward updates were rejected
Merge the remote changes before pushing again.  See the 'non-fast forward'
section of 'git push --help' for details.

This error can be a bit overwhelming at first, do not fear.
Simply put, git cannot make the change on the remote without losing commits, so it refuses the push. Usually this is caused by another user pushing to the same branch.
You can remedy this by fetching and merging the remote branch, or using pull to perform both at once.

In other cases this error is a result of destructive changes made locally by using commands like git commit --amend or git rebase.
While you can override the remote by adding --force to the push command, you should only do so if you are absolutely certain this is what you want to do. Force-pushes can cause issues for other users that have fetched the remote branch, and is considered bad practice. When in doubt, don’t force-push.

Mode details on the "Note about fast-forwards" of git push, as mentioned by Michael Mrozek in the comments.

In addition to VonC's answer,

In case you, intend to override the remote changes with your local,

  $git push --force

will do.

Quite important: this can also occur if name of the branch you are on (and want to merge) and the branch upstream are not the same. Then work flow could look like this:

git pull --rebase             # to retrieve upstream changes, replay yours on top
git push --dry-run --verbose origin HEAD:master   # always good idea: dry-runs..
git push origin HEAD:master   # actually push current branch head (non-master) to upstream master

If you are getting this error and your .git/config file is just fine then go through these steps (this is a common problem with a submodule in git repos - again do this from the submodule dir)

1. git checkout master
2. git pull
3. (merge happens in background)
4. git push

First Pull then push

git pull origin any_branch_name

I had this too and couldn't find anywhere on StackOverflow with the following useful nugget clearly stated: Git won't let you push to a different branch if your working branch has diverged from it. There's an easy fix - just switch to the branch you want to push to and merge your working branch into it. So instead of trying this:

git push origin master   <========== On "mybranch"

Do this:

git checkout master      <========== Switch to the branch you want to push to
git pull origin master   <========== Get latest from remote repository
git pull origin mybranch <========== Merge in changes from "mybranch"
======== Resolve any issues ========
git push origin master   <========== Push the merged changes