Git Commands

published: 2018-11-14

tags: dev,git

Creating a new repository

Create on Git and then clone locally
Initialize repository locally and then add a remote repository. To do this navigate to where the repository will be located. In git cmd, type
```
  git init
```

Remote Repositories (aka Remotes)

Remotes are where pushes and pulls are sourced from. Local repository can reference multiple remote repositories. “origin” is standard for the primary repository

    git remote add [remote_name] [URL]

…then push with…

    git push [remote_name] [branch]

The Staging area

Before commiting updates add them to the staging area
```
  git add
  
```
To add everthing new, changed and deleted
```
  git add --all
  
```
To add all files in a path
```
  git add [path]/
  
```
To unstage files
```
  git reset [file]
```

Undoing local changes

To revert changes, “checkout” the file. This will overwrite local changes with the latest committed version of the file in your local repository.
```
  git checkout -- [file]
```

Commiting

Files are not automatically sent to yout remote repository. They are first ‘staged’ so that groups of files can be commited together

comment every commit!

    git commit -m '[commit message]'

Undoing a commit

To undo a commit, leaving everything else intact
```
  git reset --soft HEAD^
  
```
To undo a commit and everything staged, but leave the work tree
```
  git reset HEAD^
  
```
To completely throw away all uncommitted changes, resetting everything to the previous commit
```
  git reset --hard HEAD^
  
```
This will leave un-tracked files though, to remove these call
```
  git clean -d -f
  
```

The HEAD^ denotes the commit before the current HEAD version.

Pulling/Merging

Pulling gets remote commits and merges them into your local branch. You can use pull to merge branches back into master. E.g. if you have a branch called hotfix1 on the remote origin you can merge this back into master with…

    git pull origin hotfix1

The same as calling

    git fetch

and

    git merge hotfix1

Branching

You create new branches locally

    git branch feature1

and git checkout feature1

Or you can just create and checkout with

    git checkout -b feature1

When working in a branch make sure you push the branch using

    git push [remote_name] [branch_name]

Your branch won’t be available from the remote until you push it!

To delete a local branch you can call
```
  git branch -d [branch_name]
  
```

To delete a branch from remote call

  git push [remote_name] --delete [branch_name]

e.g.

  git push origin --delete hotfix1

Tagging

Git uses two main types of tags: lightweight and annotated. A lightweight tag is very much like a branch that doesn’t change. It’s just a pointer to a specific commit

Annotated tags are stored as full objects in the Git database. They contain the tagger name, email, and date and have a tagging message (we should use these the majority of the time)

To create an annotated tag call
```
  git tag -a v1.4 -m "my version 1.4"
```
You can view a list of tags with
```
  git tag
  
```

Stashing

To keep something that is not ready for commit you can “stash” local changes

When you are ready, you can re-apply the stash against the branch

To stash all your uncommitted changes just run
```
  git stash
  
```
And then to re-apply them against your working copy run
```
  git stash apply
  
```

You can have multiple stash stacks and pick which one you want to apply

Problems

Conflicts: if two people have commited changes to the same lines of the same file you will get a conflict. Easiest approach to resolve this is to use a merge tool

Detached head: When you checkout a specific commit you are detached from the HEAD which is a pointer to the latest commit in the branch. You just need to checkout the branch again to fix this.

References

The documentation on the main Git site https://git-scm.com/doc - book https://git-scm.com/book/en/v2

Useful information on a branching strategy http://nvie.com/posts/a-successful-git-branching-model/