Git Basics

How to create a new fresh repository

How to create a new repository
Git mobile case – throwaway branches

Cleaning up: branches, remotes, pruning, etc

Git Clean Up – cleanliness is next to Godliness

Git Flow —no-ff Merging

• git checkout master
• git merge —no-ff feature-branch # nice way
• git mergetool #if there is a problem
• git mergetool -y # another option
• git checkout —theirs some-file.txt # nuke the
• git add some-file.txt

Git Flow Rebasing

• git fetch origin # pull in fresh code
• # make master up to date with git pull origin master or a reset —hard
• git checkout feature-branch
• git rebase —preserve-merges master # preserve-merges gives you the nice no-ff merge history

If you want to force squash then rebase the squash onmaster to get all new stuff from the
git rebase -s recursive -X theirs ${branch} if you want to always defer to the branch’s version.

ours and theirs in merging/rebasing

“ours” and “theirs” is relative to whether or not you are merging or rebasing. In all cases: whatever HEAD’s pointing to is “ours”

If you’re merging:

• then “ours” means the branch you’re merging into , and
• “theirs” is the branch you’re merging in.

When you’re rebasing:

• then “ours” means the commits you’re rebasing onto, the one getting the new commits while
• “theirs” refers to the commits that you want to rebase.

• given master
• br
• git checkout br
• git rebase master # rebase br to master
• ours === master
• theirs === br
• git mergetool # order in screen is: ours LOCAL | rebasing-output | theirs REMOTE

git show

• git show branch:file-name.txt > file-name.txt
• git show —pretty=“format:” —name-only schedule_versions # what files changed in this commit

Handy Commands

see what origin is set to:
git config remote.origin.url

set a new one:
git config remote.origin.url thegituser@makalu:git/cloud/walkull

Typical Flow

Here is a typical example of using Git with multiple branches.

Git Flow

git flow description
master – sacrosanct major release, split from a release branch
v1.0, vX – release branch
develop – primary development branch

typical flow

git checkout -b feature/something
multiple commits
git rebase develop # keep abreast of changes

1. don’t git merge into feature/something rebase.
   #ready for merge
   git checkout develop
   git merge —no-ff feature/something
2. nice clean branch history

Create/Apply a Patch

If you can not push to a github repo or clone/pull request create a patch:
Assumes spree and tax-render
From: Spree branch commit 5fd4937d359f3db56cc52cf43bbf430ef18d2891
$ git checkout tax-render
Switched to branch ‘tax-render’
$ git format-patch spree —stdout > spree2tax-render_branch.patch #creates patch
$ git checkout spree
Switched to branch ‘spree’
$ git apply —stat spree2tax-render_branch.patch #see the deltas, do nothing
$ git apply —check spree2tax-render_branch.patch # test application
$ git am —signoff < spree2tax-render_branch.patch # do the application of the patch.
Applying: ajax tax render fix

Create local branches

This would be used if you do not already have local branches set up , or if you never had a local copy of a particular “tracking branch” .

• git checkout -b master -f remotes/origin/master

• git checkout -b shipping -f remotes/origin/shipping

• git checkout -b communication -f remotes/origin/communication

Create Local Branches

Create a local branch

• git checkout -b vcodes

• change and commit in the new vcodes

• git merge -s resolve —squash vcodes

Refreshing local branches

In the case above you did not have a local tracking branch. If you already have a repository with a tracking branch, say master, but that branch has stale code then you will want to update that stale branch to be in synch with the remote.

• git checkout -f master (ignores/overwrites local files, and switches to that tracking branch. Still stale)

• git reset —hard

• git pull origin master

• git reset —hard

• git pull

Here they are again for cutting/pasting:

git checkout -f master

git reset —hard

git pull origin master

git reset —hard

git pull

svn revert – undoing a change in a single file.

If you have an uncommitted change that you wish to revert to the copy in your latest commit, do the following:

git checkout filename

This will checkout the file from HEAD, overwriting your change. This command is also used to checkout branches, and you could happen to have a file with the same name as a branch. All is not lost, you will simply need to type:

git checkout — filename

Make a change and commit to the local repository.

If following commands directly from the above, checkout -f to your working branch, perhaps shipping. Note this would be on some branch other than master most likely.

• edit file.txt

• git add file.txt

• git status

• git commit

get new files on this branch that someone else may have made

• git fetch

• if there are merge conflicts repeat the edit/add/status/commit process from above.

• git push

Merge in code from the most up to date version of master

• git merge -s resolve remotes/origin/master

• if there are merge conflicts repeat the edit/add/status/commit process from above.

• test to valididate

push current version to git repository

• git push origin communication

Checkout

Assuming you don’t mind losing files not yet checked in try this sequence. Creates a new branch called my-local-branch-name. and pulls in all the files needed for the remote version of dirty vendor. The “f” is force so that you don’t get merge issues (since you are merging code into your existing “working tree”

• git checkout -b my-local-branch-name -f remotes/origin/dirty-vendor

• git checkout -b dirty-vendor -f remotes/origin/dirty-vendor

Push – pushing your code to the remote repository

Use this to push your local committed code on branch “communication” up to the remote git communication (i.e. remotes/origin/communication

• git push origin communication

If instead you called your local branch comm, you would want to indicate that Comm should be pushed to communication at remote

• git push origin comm:communication

Clean and other useful things

Unmanaged files can cause conflicts. To clean your local files .

• git clean -f

Graphically view the commit history.

• gitk

Clean up old unused commits

• git reflog expire —all —expire=now —dry-run —verbose

Set the appropriate files to ignore

Add files to .git/info/exludes

• *~
• log/*
• .project
• .loadpath

Handy commands from: schacon@gmail.com

books/sites

• Git Internals
• Pro Git proGit.org

incremental changes

git add -p

viewing whole tree
gitk —all
git log —graph —all

remote servers/repositories

clone creates origin from where you pulled it.
git remote add orign git@github….
git push origin master

fetch!

git fetch

git blame -C kdkd.rb
git bisect start
git bisect bad
git bisect reset

---

from err the blog

Setup
-—

git clone
clone the repository specified by ; this is similar to “checkout” in
some other version control systems such as Subversion and CVS

Add colors to your ~/.gitconfig file:

[color] ui = auto [color “branch”] current = yellow reverse local = yellow remote = green [color “diff”] meta = yellow bold frag = magenta bold old = red bold new = green bold [color “status”] added = yellow changed = green untracked = cyan

Highlight whitespace in diffs

[color] ui = true [color “diff”] whitespace = red reverse [core] whitespace=fix,-indent-with-non-tab,trailing-space,cr-at-eol

Add aliases to your ~/.gitconfig file:

[alias] st = status ci = commit br = branch co = checkout df = diff lg = log -p

Configuration
-—————

git config e [-global]
edit the .git/config [or ~/.gitconfig] file in your $EDITOR

git config —global user.name ‘John Doe’
git config —global user.email johndoe@example.com
sets your name and email for commit messages

git config branch.autosetupmerge true
tells git-branch and git-checkout to setup new branches so that git-pull
will appropriately merge from that remote branch. Recommended. Without this,
you will have to add —track to your branch command or manually merge remote
tracking branches with “fetch” and then “merge”.

git config core.autocrlf true
This setting tells git to convert the newlines to the system’s standard
when checking out files, and to LF newlines when committing in

You can add “—global” after “git config” to any of these commands to make it
apply to all git repos .

Info
--

git diff
show a diff of the changes made since your last commit
to diff one file: “git diff — ”
to show a diff between staging area and HEAD: `git diff —cached`

git status
show files added to the staging area, files with changes, and untracked files

git log
show recent commits, most recent on top. Useful options:
—color with color
—graph with an ASCII-art commit graph on the left
—decorate with branch and tag names on appropriate commits
—stat with stats
-p with full diffs
—author=foo only by a certain author
—after=“MMM DD YYYY” ex. only commits after a certain date
—before=“MMM DD YYYY” only commits that occur before a certain date
—merge only the commits involved in the current merge conflicts

git log ..
show commits between the specified range. Useful for seeing changes from
remotes:
git log HEAD..origin/master # after git remote update

git show
show the changeset of a commit specified by , which can be any
SHA1 commit ID, branch name, or tag (shows the last commit by default)

git blame
show who authored each line in

git blame
show who authored each line in as of

git gui blame
really nice GUI interface to git blame

git whatchanged
show only the commits which affected listing the most recent first

Adding / Deleting
-———————

git add …
add , , etc… to the project

git add

add all files under directory to the project, including subdirectories

git add .
add all files under the current directory to the project

git rm …
remove , , etc… from the project

git rm $
remove all deleted files from the project

git rm —cached …
commits absence of , , etc… from the project

Staging
-——

git add …
git stage …
add changes in , … to the staging area (to be included in
the next commit

git add -p
git stage —patch
interactively walk through the current changes in the working
tree, and decide which changes to add to the staging area.

git add -i
git stage —interactive
interactively add files/changes to the staging area. For a simpler
mode , try `git add —patch`

Committing
-———-

git commit … [-m ]
commit , , etc…, optionally using commit message ,
otherwise opening your editor to let you type a commit message

git commit -a
commit all files changed since your last commit
(does not include new files)

git commit -v
commit verbosely, i.e. includes the diff of the contents being committed in
the commit message screen

git commit —amend
edit the commit message of the most recent commit

git commit —amend …
redo previous commit, including changes made to , , etc…

Branching
-———

git branch
list all local branches

git branch -r
list all remote branches

git branch -a
list all local and remote branches

git branch create a new branch named , referencing the same point in history as
the current branch

git branch
create a new branch named , referencing , which may be
specified any way you like, including using a branch name or a tag name

git branch —track
create a tracking branch. Will push/pull changes to/from another repository.
Example: git branch —track experimental origin/experimental

git branch -d delete the branch ; if the branch you are deleting points to a commit
which is not reachable from the current branch, this command will fail with a
warning.

git branch -r -d
delete a remote-tracking branch.
Example: git branch -r -d wycats/master

git branch -D even if the branch points to a commit not reachable from the current branch,
you may know that that commit is still reachable from some other branch or
tag. In that case it is safe to use this command to force git to delete the
branch.

git checkout make the current branch , updating the working directory to reflect
the version referenced by

git checkout -b
create a new branch referencing , and check it out.

git push : removes a branch from a remote repository.
Example: git push origin :old_branch_to_be_deleted

Merging
-——

git merge merge branch into the current branch; this command is idempotent and
can be run as many times as needed to keep the current branch up-to-date with
changes in

git merge —no-commit
merge branch into the current branch, but do not autocommit the
result; allows you to make further tweaks

git merge -s ours
merge branch into the current branch, but drops any changes in
, using the current tree as the new tree

Cherry-Picking
-—————-

git cherry-pick [—edit] [-n] [-m parent-number] [-s] [-x]
selectively merge a single commit from another local branch
Example: git cherry-pick 7300a6130d9447e18a931e898b64eefedea19544

Squashing
-———
WARNING: “git rebase” changes history. Be careful. Google it.

git rebase —interactive HEAD~10

squash the last 10 commits into one big commit

Conflicts
-———

git mergetool
work through conflicted files by opening them in your mergetool and choosing left/right chunks. The merged result is staged for
commit.

For binary files or if mergetool won’t do, resolve the conflict manually and
then do:

git add [ …]

Once all conflicts are resolved and staged, commit the pending merge with:

git commit

Sharing
-——

git fetch
update the remote-tracking branches for .
Does not initiate a merge into the current branch .

git pull
fetch changes from the server, and merge them into the current branch.
Note: .git/config must have a [branch “some_name”] section for the current
branch, to know which remote-tracking branch to merge into the current
branch. Git 1.5.3 and above adds this automatically.

git push
update the server with your commits across all branches that are COMMON
between your local copy and the server. Local branches that were never pushed
to the server in the first place are not shared.

git push origin update the server with your commits made to since your last push.
This is always required for new branches that you wish to share. After the
first explicit push, “git push” by itself is sufficient.

Reverting
-———

git revert
reverse commit specified by and commit the result. This does not do
the same thing as similarly named commands in other VCS’s such as “svn revert”
or “bzr revert”, see below

git checkout
re-checkout , overwriting any local changes

git checkout .
re-checkout all files, overwriting any local changes. This is most similar to
“svn revert” if you’re used to Subversion commands

Fix mistakes / Undo
-————————

git reset —hard
abandon everything since your last commit; this command can be DANGEROUS. If
merging has resulted in conflicts and you’d like to just forget about the
merge, this command will do that.

git reset —hard ORIG_HEAD
undo your most recent successful merge and any changes that occurred
after. Useful for forgetting about the merge you just did. If there are
conflicts , use “git reset —hard”
instead.

git reset —soft HEAD^
forgot something in your last commit? That’s easy to fix. Undo your last
commit, but keep the changes in the staging area for editing.

git commit —amend
redo previous commit, including changes you’ve staged in the meantime.
Also used to edit commit message of previous commit.

Plumbing
-——-

test = $
determine if merging sha1-B into sha1-A is achievable as a fast forward;
non-zero exit status is false.

Stashing
-——-

git stash save
save your local modifications to a new stash

git stash apply
restore the changes recorded in the stash on top of the current working tree
state

git stash pop
restore the changes from the most recent stash, and remove it from the stack
of stashed changes

git stash list
list all current stashes

git stash show -p
show the contents of a stash – accepts all diff args

git stash clear
delete current stashes

Remotes
-——

git remote add
adds a remote repository to your git config. Can be then fetched locally.
Example:
git remote add coreteam git://github.com/wycats/merb-plugins.git
git fetch coreteam

git push :refs/heads/ delete a branch in a remote repository

git push :refs/heads/
create a branch on a remote repository
Example: git push origin origin:refs/heads/new_feature_name

git push +:
create a branch on a remote repository based on +
Example: git push origin +master:my_branch

git remote prune
prune deleted remote-tracking branches from “git branch -r” listing

Submodules
-———-

git submodule add <path/to/submodule>
add the given repository at the given path. The addition will be part of the
next commit.

git submodule update [—init]
Update the registered submodules . —init is needed the first time.

git submodule foreach
Executes the given command within each checked out submodule.

Remove submodules

1. Delete the relevant line from the .gitmodules file. 2. Delete the relevant section from .git/config. 3. Run git rm —cached path_to_submodule . 4. Commit and delete the now untracked submodule files.

Git Instaweb
-————-

git instaweb -httpd=webrick [-start | —stop | —restart]

Environment Variables
-—————————

GIT_AUTHOR_NAME, GIT_COMMITTER_NAME
Your full name to be recorded in any newly created commits. Overrides
user.name in .git/config

GIT_AUTHOR_EMAIL, GIT_COMMITTER_EMAIL
Your email address to be recorded in any newly created commits. Overrides
user.email in .git/config