Setting Up Git

git config --list – List all current Git configurations

git config --global user.email – Check user email

git config --global user.name – Check username

git config --global user.name "myname" – Change username, for all repo

git config --global user.email "email@example.com" – Change user email, for all repo

git config user.<email |name> "email@example.com" – For only current repo

git config --global core.autocrlf <true | input | false> – Configure line ending of file

See Information in Git

git show – Show some useful info in local git

git status – Show branch, working status

git ls-files . --ignored --exclude-standard --others – List ignored files

git ls-files . --exclude-standard --others – List untracked files

Changes Between Commits (file changes)

git diff <files> – show what have changed for modified files that haven’t been staged (modified files in git status)

git diff --stat <files> – show statistics of files change

$ git diff --stat backup.sql
 backup.sql | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

git diff origin/master..HEAD – Show change detail of commits for unpushed (Unsynchronized Changes) commits

Commit History

git log – List commits made in that repository in reverse chronological order

git log -p -2 – List commits and shows the difference (the patch output) introduced in each commit. Limit the number of log entries displayed, such as -2 will show only the last two entries

git log --stat – See some abbreviated stats for each commit

git log origin/master..HEAD – Show commit message for unpushed (Unsynchronized Changes) commits

Remote’s Repository

git remote -v – Check remote repo this git project associate with

git remote rm origin – Remove local git project origin (then can add a remote origin later)

git remote add origin https://github.com/USERNAME/REPOSITORY.git – Add remote repo in Github to the origin of this local Git project

git remote set-url origin https://github.com/USERNAME/REPOSITORY.git – To Http

git remote set-url origin git@github.com:USERNAME/REPOSITORY.git – To SSH

Working with Git

git status – Show status of current environment

git add <file | . > – Add a modified file or all files (using .) to the stage area

git reset -q HEAD [files] – Remove all staged files or specific files from stage area

git commit -m "a message" – Commit the changes of staging files to local repository

git stash – Discard all local changes, but save them for possible re-use later

git checkout -- <file> – Discarding local changes (permanently) to a file

git checkout -- . – Discarding local changes (permanently) to all files

git clean -df – Remove all untracked folders/files from the repo

git rm -r --cached <file or folder name> – Remove file or folder from being tracking

git reset --hard – Discard all local changes to all files permanently

Rollback to a previous git comment (need a commit -id)

git reset --hard <old-commit-id>
git reset --hard 57e86ca            # rollback to commit 57e86ca

# then push to remote with -force to overwrite
git push -f <remote-name> <branch-name>

To clear all updates made to the current repo:

git checkout -- .
git clean -df

Cloning Repository

git clone git@github.com:karanokara/Hello-world.git – Clone from GitHub to current folder, using SSH key, create a new folder as the repo name as ‘Hello-world’

git clone user@123.123.0.123:/Hello-world.git hello – Clone from remote host, using SSH key, to current user’s folder ‘hello’, or create it

git clone https://github.com/karanokara/repo.git – Clone from GitHub, using https, will prompt for username and password

Pull Repository

git pull <remote-name> <branch-name> – Pull the latest commit from origin remote repository, usually from “master” branch

git pull github new-feature – Pull the latest commit from “github” remote repository, from “new-feature” branch

Push Repository

git push [-u: enter account credential] <remote-name> <branch-name> – Push local Committed updates to the origin remote repository, branch name may be “master” or others

Working with Branches

git fetch -a – Fetch remote branches to local

git branch [-a: local & remote; -r: remote] – Listing branches (local, -a for local & remote)

git checkout <branch-name> – Switching branch, “branch-name” or “origin/<branch-name>”

git checkout -b <branch-name> – Create new branch base on current branch

There are 3 different branches: Local, Local remote-tracking, Remote origin.

git branch -d <branch-name> – Delete a local branch

git branch -d -r <remote-name/branch-name> – Delete a remote-tracking branches (need to push to delete its remote branch)

git push origin -d <branch_name> – Delete a remote branch (and also its remote-tracking branch)

Removes/delete (Prunes) all obsolete local remote-tracking branches for any remote branches that no longer exist on the remote

git remote prune origin
# or
git fetch origin --prune
git fetch origin -p

Generating SSH key and Adding to the ssh-agent

After adding ssh-rsa key to Github, no need to type password when there is a push update to a remote repository.
ssh-keygen -t rsa [-f <filename>] -b 4096 -C "your_email@example.com" – Generating a new SSH key ( whatever email, doesn’t matter, e.g. root@toshiba )

> Enter passphrase (empty for no passphrase): [Type a passphrase]
> Enter same passphrase again: [Type passphrase again] – Hit enter without passphrase here

eval $(ssh-agent -s) – Ensure the ssh-agent is running with output as Agent pid 12345

ssh-add ~/.ssh/id_rsa – Add generated SSH private key to the ssh-agent.

Finally, Copy content of cat ~/.ssh/id_rsa.pub, the public ssh-rsa key to the Github account.

For automatically adding private key to the ssh agent every time login via SSH:

Config the SSH startup script sudo vim ~/.bashrc, add to the end of file:

eval $(ssh-agent -s)             # Open a ssh agent
ssh-add /home/user/.ssh/id_rsa    # Add pri key to agent 

To delete the invalid key such as after renewing a key:

ssh-keygen -R <hostname/ip>