Git Cheatsheet

Don't believe anything here…. :-} At the moment this is just for my benefit and is being added to and edited as I discover “stuff”….

Background to Git

https://git-scm.com/book/en/v2/Getting-Started-About-Version-Control

Usernames and passwords

It's recommended that two factor authentication is set up for Github accounts. This does introduce a few subtle gotchas:-

If 2fa is enabled, your github username and password used to log in to the web portal will not work for git clone https://github.com/YOUR_REPO, this will return remote: Invalid username or password. The solution is to use a Personal Access Token, this is set up in the security section of the Github website config pages. It is described here:- https://help.github.com/articles/creating-a-personal-access-token-for-the-command-line/
If you have two repos on a machine (OsX) which need two different logins, modify the repo URL to include the username to log in as, this is set in .git/config (eg. url = https://username@github.com/username/pythonapp.git), otherwise the github.com keychain access logins will be used. This may be true for linux too.

You can save the password or PAT manually:-

url = https://username:password@github.com/username/pythonapp.git

You can add a username and password at the time you do a clone with:-

$ git clone https://username:pers-acc-tok@repo-url.com/pathto/your-repo.git

An alternative way is to use a credential store:-

$ git config credential.helper store
or
$ git config --global credential.helper store

Your creds will be stored in your home directory (~/.git-credentials)

Add Git Branch to PS1 prompt

Thanks Dharmesh for the info! You know who you are!

In your .bash_profile in your home directory, add:-

git_branch() {
  git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/ (\1)/'
}

export PS1="\u@\h \W\[\033[32m\]\$(git_branch)\[\033[00m\]$ "

This gives:-

laptop economy-7 <fc #00ff00>(abc-123)</fc> $

Starting a new repo

git config

$ git config --global user.email me@mycomp.co.uk
$ git config --global user.name Real Name

You can see the current settings in force with:-

$ git config --list
core.excludesfile=~/.gitignore
core.legacyheaders=false
...edited...
color.ui=auto
color.interactive=auto
alias.s=status
alias.a=!git add . && git status

Note this also shows aliases which are useful shorthand:-

$ git s
On branch master
Your branch is up to date with 'github/master'.

Untracked files:
  (use "git add <file>..." to include in what will be committed)

	fullstack-expt/.terraform/

nothing added to commit but untracked files present (use "git add" to track)

git init

Creates an empty or reinitialise an existing repo, this writes the .git directory and adds appropriate subdirectories.

$ git init
Initialised empty Git repository in /home/andrew/ansible/testplays/cis-awsLinux2/.git/

git clone

Pulls a repo down from <URL>

git clone <url>

git branch (create and delete)

Adding and listing branches

git branch <name>	create new branch
git checkout -b <name>	create new branch and checkout
git branch	List branches
git branch -a	List all branches, local and remote

Deleting local and remote branches

`git branch -d <branch>`	safe delete branch id merged ok
`git branch -D <branch>`	delete without warnings
`git push origin –delete <branch>`	deletes remote branch only

git checkout

Create a new branch and checkout

$ git checkout -b ajs/newBranch

Switch to different branch

$ git checkout ajs/emptyDirWarning
Switched to branch 'ajs/emptyDirWarning'

And back to master branch

$ git checkout master
Switched to branch 'master'
Your branch is up-to-date with 'origin/master'.

Also, to create a local branch from a remote one try this:-

git checkout -t remotes/repo/branch

Create new, empty branch

This will create a new branch not associated with any existing branches. Useful for entirely new code where you don't need to base your branch on any existing code.

$ git switch --orphan master-tmp

git add

Add file to local repo, either single file:-

$ git add README.md

Or files which match an expression:-

$ git add *

Also rm removes files from the working tree before commit

$ rm testfile2 
$
$ git rm testfile2

git commit

$ git commit -m "initial commit"
[master (root-commit) 5730eea] initial commit
 1 file changed, 1 insertion(+)
 create mode 100644 README.md
$

-m is a message stored to illustrate the changes being committed. If you forget the -m, git will open up an editor for you to create one. If you cancel, the commit is cancelled.

Don't forget that changed files need to be added (git add) before the commit will work!

git commit -a will add all files changed, or git commit <file> -m “comment” to add just one file.

git remote add

Adds a remote named <name> for the repository at <url>. Convention seems to be using origin, but you could use a more descriptive name, eg. codeCommit or gitHub. I think this would allow you to set two remotes and push to either or.

Setting two remotes seems a way to move a repo from one repository host to another (eg. Github to AWS Code Commit).

git remote add [-t <branch>] [-m <master>] [-f] [–[no-]tags] [–mirror=<fetch|push>] <name> <url>

$ git remote add origin https://github.com/user/RepoName.git
or
$ git remote add codeCommit https://git-codecommit.eu-west-1.amazonaws.com/v1/repos/RepoName

git remote delete

Deletes a remote URL

$ git remote rm CodeCommit

Verify remote URL

$ git remote -v

git push

$ git push -u origin master
Username for 'https://github.com': UserName
Password for 'https://UserName@github.com': <Hidden> (needs to be Personal Access Token for 2fa access)
Counting objects: 3, done.
Writing objects: 100% (3/3), 246 bytes | 0 bytes/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To https://github.com/mycorp/repo1.git
 * [new branch]      master -> master
Branch master set up to track remote branch master from origin.
$

If you have a local branch and a remote which do not share a common history, Git will refuse to merge them. Generally, this is a good idea, but if you know you are right and Git is wrong, you can use –allow-unrelated-histories to force this push. This will merge the upstream branch with your changes. It may not be what you expect, so this is a “not used often” command.

AWS CodeCommit *REQUIRES* a “helper”, see Amazon Web Services CLI

$ git config --global credential.helper cache

If this doesn't work it may fail with a message:-

error: src refspec master does not match any.
error: failed to push some refs to 'origin'

The reason for this is that there is only a local master branch created when commits have been done, so create or touch a file, add it and then repush to remote.

Push local branch to remote repo:-

git push --set-upstream origin name-of-localBranch

git pull

$ git pull codeCommit
remote: Counting objects: 3, done.
Unpacking objects: 100% (3/3), done.
From https://git-codecommit.eu-west-1.amazonaws.com/v1/repos/REPO_NAME
   4cec434..32ac5a2  master     -> codeCommit/master
Updating 4cec434..32ac5a2
Fast-forward
 FileName | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

Note, git fetch will get updates from the origin, but will not merge with any local changes. git pull is the same as git fetch followed by a git merge. git fetch will never change your local copy or branch, but git pull will update your local branch to it's remote version, which you may not want.

git fetch

git fetch will get updates from the origin, but will not merge with any local changes.

git log

Use git log to show the last commits:-

me@puppet:~/$ git log
commit 15fb2ac3ec05c423465334526c38fd7705fb13033
Author: A* <me@mydomain.co.uk>
Date:   Mon Oct 8 17:26:48 2018 +0100

    Initial commit
me@puppet:~/$

git status

Check files which need commiting:-

$ git status
On branch master
Your branch is up-to-date with 'gitHub/master'.
nothing to commit, working directory clean
$

Following any local changes, this will show what needs to be committed:-

$ git status
On branch master
Your branch is up-to-date with 'gitHub/master'.
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)
 
	modified:   roles/cisHardening/tasks/section_06_level1.yml
 
no changes added to commit (use "git add" and/or "git commit -a")
$

git tag

Create a release and add a tag to it, this creates a new HEAD from master which cannot be modified further.

$ git tag -a 0.1.1 -m "Updated Tags"
$ git push --tags

...work...

$ git tag -a 1.0.0 -m "Updated Tags, ready for production."
$ git push --tags

$ git tag -n
1.0.0           Updated Tags ready for production.
v0.1.0          Merge pull request #9 from JSainsburyPLC/ajs/TagAddition
v0.1.1          Updated Tags

git diff

This works even for files outside any repo.

git diff --no-index -- file.a file.b

Adding some new files to existing repo

In summary:-

git add *
git push -u origin master
git commit -m “File commit”
git push -u origin master
git status

Transcript:-

$ git add *
 
$ git push -u gitHub master
Username for 'https://github.com': UserName
Password for 'https://UserName@github.com': 
Branch master set up to track remote branch master from gitHub.
Everything up-to-date
$
 
$ git commit -m "File commit"
[master a0ed44c] File commit
 43 files changed, 2580 insertions(+)
 create mode 100644 ansible_id_rsa
 create mode 100644 examples.txt
 create mode 100644 hosts-ansible.ans
 create mode 100644 main.yml
...edited....
 create mode 100644 roles/updateSystem/vars/main.yml
 create mode 100644 test.yaml
$ 
$ 
$ git push -u gitHub master
Username for 'https://github.com': UserName
Password for 'https://UserName@github.com': 
Counting objects: 56, done.
Compressing objects: 100% (48/48), done.
Writing objects: 100% (56/56), 18.07 KiB | 0 bytes/s, done.
Total 56 (delta 4), reused 0 (delta 0)
remote: Resolving deltas: 100% (4/4), done.
To https://github.com/UserName/repo1.git
   5730eea..a0ed44c  master -> master
Branch master set up to track remote branch master from gitHub.
$
 
$ git status
On branch master
Your branch is up-to-date with 'gitHub/master'.
nothing to commit, working directory clean
$

Pulling existing repo to local machine

List all branches available

$ git branch -a
* master
  remotes/codeCommit/Devel
  remotes/codeCommit/add-integration
  remotes/codeCommit/add-scan

git clone

This will pull all the branches from the remote repo to the local repo.

config@app-test:~$ git clone https://github.com/mycorp/repo1.git
Cloning into 'repo1'...
Username for 'https://github.com': user
Password for 'https://user@github.com': 
remote: Counting objects: 5337, done.
remote: Compressing objects: 100% (88/88), done.
Receiving objects: 100% (5337/5337), 145.80 MiB | 638 KiB/s, done.
Resolving deltas: 100% (3445/3445), done.
config@app-test:~$ 
config@app-test:~$ ls -l
total 4
drwxr-xr-x 12 config config 4096 Nov 16 15:13 repo1
config@app-test:~$

git pull

This will update an existing local repo with changes.

config@server1:~/repo1$ git pull
Username for 'https://github.com': user
Password for 'https://user@example.com': 
remote: Counting objects: 185, done.
remote: Compressing objects: 100% (9/9), done.
remote: Total 185 (delta 73), reused 71 (delta 71), pack-reused 105
Receiving objects: 100% (185/185), 2.91 MiB | 1.76 MiB/s, done.
Resolving deltas: 100% (129/129), completed with 43 local objects.
From https://github.com/mycorp/repo1
   b18c497..31d0b7f  develop    -> origin/develop
 * [new branch]      feature/debug-thumbnail -> origin/feature/debug-thumbnail
   a414060..9ef89a8  master     -> origin/master
 * [new tag]         v3.11.5    -> v3.11.5
Auto-merging src/tests/Generator.h
Merge made by the 'recursive' strategy.
 scripts/status.sh                           |    2 +-
 src/Generator.cpp                  |   89 +++++---------

....edited....

 src/tests/Request.h                  |   35 ++++++
 55 files changed, 873 insertions(+), 466 deletions(-)
 create mode 100644 src/tests/FileUtilTest.cpp
 create mode 100644 src/tests/FingerprintProcessorTest.cpp
 create mode 100644 src/tests/IntegrationTests/RtfpdTestBase.py
 mode change 100644 => 100755 src/tests/IntegrationTests/StartIntegrationTests.py
 create mode 100755 src/tests/IntegrationTests/testBlackMegicCardLogging.py
 create mode 100755 src/tests/build_scripts/grepLSOF.sh
 create mode 100644 src/tests/s/AudioFingerprintGenerator.h
 rename src/tests/{DataGeneratorTest.h => s/DataGenerator.h} (83%)
 create mode 100644 src/tests/s/FingerprintProcessor.h
 create mode 100644 src/tests/s/GeneratorCollection.h
 create mode 100644 src/tests/s/Request.h
config@server1:~/repo1$

git rebase

Use this to merge updates/changes in Master to local branch.

git status
git checkout master
git pull
git checkout ajs/branchName
git rebase origin/master
git status
 
Resolve any conflicts here. Add changed files again.
 
git depermission.py 
git status
git rebase --continue

git status

  
config@server1:~/repo1/scripts$ git status
# On branch develop
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#       new file:   fpamenu.sh
#
# Changes not staged for commit:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#       modified:   menu.sh
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#       test-printf.sh
#       test-setip.sh
config@server1:~/repo1/scripts$

git add, commit and push

Same as the above content git add, add new files to the local repo with add, commit to the local repo and then push to the remote repo.

git actions with specific ssh key

Use git environment variable GIT_SSH_COMMAND:-

$ GIT_SSH_COMMAND='ssh -i ~/.ssh/bitbucket' git push --set-upstream origin ajs/mybranch

Restoring files which are deleted

use this to find the commit id of the last commit where the file was deleted:-

$ git rev-list -n 1 HEAD -- ansible_id_rsa
3d83c24b89d7b27aecf99fecef54982d3ecf0620
$

Then use this commit id to checkout the file from a specific point in time:-

$ git checkout 3d83c24b89d7b27aecf99fecef54982d3ecf0620^ -- ansible_id_rsa

Backing out changes

Problem:- On local master branch by mistake and attempt to merge local branch to it, meant to merge one local branch with another.

Solution:- running git merge <branchname> whilst master is checked out merged changes to the wrong place, to revert master back to as it was, I ran git reset –hard origin/master

NOTE –hard can delete local files you may wish to keep!! Excercise caution!!

Local master is ahead of remote master

Very simiar fix to above, somehow local master was ahead of local, a reset –hard was needed:-

$ git status
On branch master
Your branch is ahead of 'origin/master' by 5 commits.
  (use "git push" to publish your local commits)
 
 
$ git reset --hard origin/master
HEAD is now at xxxx Pull request #24: Minor fixes plus renaming
 
$ git status
On branch master
Your branch is up to date with 'origin/master'.

Git Aliases

from ~/.gitconfig:-

[alias]
	lga = log --graph --oneline --all --decorate
        co = checkout
        lg1 = log --graph --abbrev-commit --decorate --date=relative --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar) %G? %C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)' --all

Thanks to John Buxton for the lg1 alias

Viewing aliases in effect:-

$ git alias
...
edited
...
cm	 => commit -m
co	 => checkout
d	 => diff
...
s	 => status

AWS CodeCommit

See page on AWS Codecommit with a credential helper:- AWS CodeCommit cli

AWS cli code to create a repository in CodeCommit.

$ aws codecommit create-repository --repository-name CIS-Hardening-AWS_Linux2 --repository-description "Repo for ansible code to harden aws Linux2 image."
{
    "repositoryMetadata": {
        "repositoryDescription": "Repo for ansible code to harden aws Linux2 image.",
        "cloneUrlSsh": "ssh://git-codecommit.eu-west-2.amazonaws.com/v1/repos/CIS-Hardening-AWS_Linux2",
        "repositoryId": "91fb59e3-833e-4705-8e1c-xxxxx",
        "lastModifiedDate": 1537199788.236,
        "accountId": "1234567789",
        "repositoryName": "CIS-Hardening-AWS_Linux2",
        "Arn": "arn:aws:codecommit:eu-west-2:581230658448:CIS-Hardening-AWS_Linux2",
        "cloneUrlHttp": "https://git-codecommit.eu-west-2.amazonaws.com/v1/repos/CIS-Hardening-AWS_Linux2",
        "creationDate": 1537199788.236
    }
}

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Table of Contents

Git Cheatsheet

Background to Git

Usernames and passwords

Add Git Branch to PS1 prompt

Starting a new repo

git config

git init

git clone

git branch (create and delete)

Adding and listing branches

Deleting local and remote branches

git checkout

Create new, empty branch

git add

git commit

git remote add

git remote delete

Verify remote URL

git push

git pull

git fetch

git log

git status

git tag

git diff

Adding some new files to existing repo

Pulling existing repo to local machine

List all branches available

git clone

git pull

git rebase

git status

git add, commit and push

git actions with specific ssh key

Restoring files which are deleted

Backing out changes

Local master is ahead of remote master

Git Aliases

AWS CodeCommit