GIT for Ubuntu

Krishna Neupane

Jan 2, 2023

Getting Started

Installation

 
sudo apt-add-repository ppa:git-core/ppa
sudo apt-get update
sudo apt-get install git
git --version

Create Repository

Create new folder 'recipes' and change path to new 'recipes' folder
```
 
mkdir recipes && cd recipes
```
Create empty repository ('.git' hidden folder is created)
```
 
git init
```
Set the username to be attached to commits
```
 
git config user.name "bob"
```

Set the email address to be attached to commits

 
git config user.email "bob@somewhere.com"

Set the editor to be used with git edits
```
 
git config core.editor vim
```
Set the tool to be used with git merges
```
 
git config merge.tool meld
```
Set the default LF formatting
```
 
git config core.autocrlf input
```
Enable colourization
```
 
git config color.ui always
```
Set push default
```
 
git config push.default simple
```
The first commit of a repository can not be rebased like regular commits, so it’s good practice to create an empty commit as your repository root
```
 
git commit -m "root"
```
Create empty readme markdown file
```
 
touch README.md
```

Append some content to README.md file

 
echo "# Recipes README" >> README.md

Display contents of README.md file
```
 
cat README.md
```
Display all new or modified files (changes)
```
 
git status
```
Add all current changes to next commit
```
 
git add .
```
OR

Specifically add README.md to next commit
```
 
git add README.md
```
Commit all current changes
```
 
git commit -m "Add README"
```
Link local repository to a remote (like github, gitlab, bitbucket, tfs etc) repository
```
 
git remote add origin [url]
```
Push all changes to remote repository
```
 
git push -u origin master
```

Configuration

Git configuration can be managed at 3 levels of specificity:

Local - applies only to current git repository
Global - applies to all git repositories for the current user
System - applies to all git repositories for all users

Local Configuration

Run the following commands via the terminal from the root of your git project (where the .git hidden folder resides) to view or edit a list of local settings.

View and Edit Local Config

Command | Description

 
cat ./.git/config | View local config
vim ./.git/config | Edit local config
git config --edit | Use default configured editor to edit local config

Get Local Config Settings

Command | Description

 
git config --list | List all git config settings
git config user.name | Get username config setting
git config user.email | Get email config setting
git config core.autocrlf | Get autocrlf (see note below) config setting
git config core.editor | Get editor config setting
git config merge.tool | Get merge tool config setting

Set Local Config Settings

Command | Description

 
git config user.name "bob" | Set username config setting
git config user.email "bob@bob.com" | Set email config setting
git config core.autocrlf input | Set autocrlf (see note below) config setting
git config core.editor vim | Set editor config setting
git config merge.tool meld | Set merge tool config setting

Global Configuration

Run the following command via the terminal from any location

View and Edit Global Config

Command | Description

 
cat ~/.gitconfig | View global config
vim ~/.gitconfig | Edit global config
git config --global --edit | Use default configured editor to edit global config

Get Global Config Settings

Command | Description

 
git config --global --list | List all git config settings
git config --global user.name | Get username config setting
git config --global user.email | Get email config setting
git config --global core.autocrlf | Get autocrlf (see note below) config setting
git config --global core.editor | Get editor config setting
git config --global merge.tool | Get merge tool config setting

Set Global Config Settings

Command | Description

 
git config --global user.name "bob" | Set username config setting
git config --global user.email "bob@bob.com" | Set email config setting
git config --global core.autocrlf input | Set autocrlf (see note below) config setting
git config --global core.editor vim | Set editor config setting
git config --global merge.tool meld | Set merge tool config setting

System Configuration

Run the following commands via the terminal from any location

First check that system wide config exists.

 
ls /etc/gitconfig

View and Edit System Config

Command | Description

 
cat /etc/gitconfig | View global config
vim /etc/gitconfig | Edit global config
git config --system --edit | Use default configured editor to edit system config

Get System Config Settings

Command | Description

 
git config --system --list | List all git config settings
git config --system user.name | Get username config setting
git config --system user.email | Get email config setting
git config --system core.autocrlf | Get autocrlf (see note below) config setting
git config --system core.editor | Get editor config setting
git config --system merge.tool | Get merge tool config setting

Set System Config Settings

Command | Description

 
git config --system user.name "bob" | Set username config setting
git config --system user.email "bob@bob.com" | Set email config setting
git config --system core.autocrlf input | Set autocrlf (see note below) config settinsystem
git config --system core.editor vim | Set editor config setting
git config --system merge.tool meld | Set merge tool config setting

A note on autocrlf

One can instruct Git to convert CRLF to LF on commit but not the other way around by setting core.autocrlf to input. This setup means that one can use CRLF endings in Windows checkouts, but with LF endings on Mac and Linux systems. In order to do this, run any one of the following commands depending on required specificity.

Command | Specificity

 
git config core.autocrlf input | local
git config --global core.autocrlf input | global
git config --system core.autocrlf input | system

Alias Configuration

Create alias to display log summary of commit history

 
git config --global alias.log-summary "log --all --pretty=format:'%h %ad - %s%d [%an]' --graph --date=short"

Create alias to display commit history as a graph

 
git config --global alias.log-graph "log --oneline --decorate --graph"

Resetting HEAD pointer to previous commit and preserve all changes as unstaged changes
```
 
git config --global alias.unstage "reset HEAD --"
```

Commands

Create Repositories

Command | Description

 
git init | created new local repository in current directory
git init [project-name] | create new local repository with specified name
git clone [url] | downloads a project and its entire version history

Manage Local Changes

Command | Description

 
git status | Lists all new or modified files to be committed
git status -u | Like *git status*, but also lists all untracked files even files inside directories)
git status --ignored | List all files and folders that are currently ignored (based on .gitignore file)
git add . | add all new and modified files to next commit
git add . -n | do dry run for add all new and modified files to next commit
git add [file-name] [file-name] | adds specified files to next commit
git commit -m "descriptive message" | records file snapshots permanently n version history
git commit -m "descriptive message" --amend | add current changes to previous commit
git commit --amend --no-edit | add current changes to previous commit using message from previous commit
git log @{u}.. | display a list of pending commits (commits that have not been pushed)

Undo Changes

git revert

Using 'git revert' is a safe way of undoing commits. Instead of removing a commit, a new commit is created with all the changes undone. Use 'git revert' when you want to remove a specific commit from the history but you still wish to preserve any changes from that commit.

Command | Description

 
git revert [commit] | undo specified commit

git reset

Using 'git reset' is essentially a permanent undo meaning that there is no way to access original changes.

Command | Description

 
git reset HEAD -- [file] | Unstage all changes to previous commit but eave working directory unchanged. The '--' is used to separate paths from revisions
git reset [file] | Equivalent to above as HEAD (previous commit) is ptional and is used by default
git reset --hard | Unstage all changes to match working directory of last ommit. All uncommited changes are lost
git reset [commit] | Unstage all changes to specified commit but preserve uncommited changes
git reset --hard [commit] | Unstage all changes to match working directory of specified commit. All uncommited changes are lost

Synchronize Changes

Command | Description

 
git remote -v | show list of remotes
git remote show [remote] | show information about remote
git remote add [short-name] [url] | add new remote repository named *[short-name]*
git push -u origin --all | push local repository to remote
git push | push local changes to remote
git pull | download changes and merge into HEAD
git fetch | download object and refs
git fetch origin | get data only from origin
git fetch --all | get data from all remotes
git fetch --all --prune | get data for all remotes and remove all deleted data

Manage Branching

Command | Description

 
git branch | show list of local branches
git branch -r | show list of remote branches
git branch -a | show list of both local and remote branches
git branch -v | show list of branches along with details of last commit on each branch
git branch -vv | like *git branch -v* but also shows which branches are tracked
git show-branch | shows the commit ancestry graph
git checkout [branch-name] | switch from current branch to *[branch-name]*. Switches HEAD branch
git checkout -b [branch-name] | create new branch called *[branch-name]* and switch to it
git branch --merged | see which branches are already merged into the branch you’re on
git branch --no-merged | see all the branches that contain work you haven’t yet merged in
git branch -d [branch-name] | safe delete *[branch-name]*. will not delete branch if there are any uncommited changes
git branch -D [branch-name] | force delete *[branch-name]* ignoring any uncommitted changes
git push --set-upstream origin [branch-name] | share and transfer *[branch-name]* to remote server
git merge [branch-name] | combines the specified branch’s history into the current branch
git push origin --delete [branch-name] | deletes remote branch called [branch-name]
git fetch && git checkout [branch-name] | checkout remote branch

Manage Commits

Command | Description

 
git log @{u}.. | display a list of pending commits (commits that have not been pushed)
git cherry-pick abc123 | add specific commit (abc123) to current branch

Manage Tags

Command | Description

 
git tag | show a list of existing tags
git tag -a V1.0 -m "Created V1.0 release." | create an annotated tag (the preferred approach)
git show tag V1.0 | show information relating to specified tag
git tag -d V1.0 | remove tag from repository
git checkout -b [branch-name] [tag-name] | You can’t really check out a tag in Git, since they can’t be moved around. If you want to put a version of your repository in your working directory that looks like a specific tag, you can create a new branch at a specific tag with '`git checkout -b [branch-name] [tag-name]`'
git push --set-upstream origin [tag-name] | share and transfer tag *[tag-name]* to remote server
git push --set-upstream origin --tags | share and transfer all tags to remote server

GIT log

Command | Description

 
git log | display commit history
git log -10 | display last 10 commits
git log -p -1 | display differences in last commit
git log --pretty=oneline | short | full | fuller` | display commit history using specified format
git log --pretty=oneline -2 | display last 2 commits using one line per commit
git log --pretty=oneline --author='' | display commit history filtering by author
git log --pretty=oneline --since='5 minutes ago' | display commit history for last 5 minutes
git log --pretty=oneline --until='5 minutes ago' | display commit history until 5 minutes ago
git log --all --pretty=format:'%h %ad \| %s%d [%an]' --graph --date=short | custom log format
git log --oneline --decorate --graph | another custom log format

Formats:

--pretty="..." defines the format of the output.
%h is the abbreviated hash of the commit
%d are any decorations on that commit (e.g. branch heads or tags)
%ad is the author date
%s is the comment
%an is the author name
--graph informs git to display the commit tree in an ASCII graph layout
--date=short keeps the date format nice and short

For More please Visit Git Documentation for Ubuntu

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