git help <command>
git help branch
git config --global core.autocrlf input
git show HEAD
git show HEAD^
git show HEAD~
git show HEAD~3
git show ed23ab
git ls-tree HEAD
git ls-tree HEAD^
git ls-tree HEAD mydir/
git log --author="prabal"
git log --grep="notes"
git log small-linklist/src/
git log 3ed12f..HEAD
git log --oneline --decorate --graph --all
git diff master..other_branch
git diff other_branch..master
git diff 63d2344..52acfe2
git diff
git log -p
shows all (diff) what was changed in each of the commits, p (patch)
git log --stat
show only which files changed in all commits
git log -3 --stat
shows only which files changed in the previous 3 commits
git show 1efdff small-linklist/src/node.c
shows what was changed in this file in this commit id
git branch
list of branches
git branch <new_branch_name>
creates a new branch from the tip of the current branch, but does not switch to it
git checkout <pre_existing_branch_name>
switches to that branch
git checkout -b <new_branch_name>
creates a new branch (from the tip of the current branch) and switches to it.
The HEAD is a pointer pointing to the place (commit) from where new commits will be made.
cat .git/HEAD can be used to show the branch which the HEAD points to now.
ls -la .git/refs/heads can be used to show what all branches the HEAD has the reference of.
The directory contains a listing of all te branches -
devp@IdeaPad:/mnt/d/github/small-linklist$ ls -la .git/refs/heads
total 0
drwxrwxrwx 1 devp devp 4096 Apr 30 13:35 .
drwxrwxrwx 1 devp devp 4096 Apr 30 13:35 ..
-rwxrwxrwx 1 devp devp 41 Apr 30 13:35 main
The contents of each of these files is the commit to which the HEAD would point when switched to that branch.
devp@IdeaPad:/mnt/d/github/small-linklist$ cat .git/refs/heads/main
89810c8b078dfa35872a6617bc5a2e22a6ee5deb
devp@IdeaPad:/mnt/d/github/small-linklist$ git log -1
commit 89810c8b078dfa35872a6617bc5a2e22a6ee5deb (HEAD -> main, origin/main, origin/HEAD)
Author: devprabal <ghjxvnjd@gmail.com>
Date: Fri Apr 29 22:45:37 2022 +0530
init gcov, lcov support
If there are uncommit changes in a branch and we are trying to switch to another branch, then we can switch if the changes are untracked or if the changes do not conflict. Else, we will need to either commit changes, discard the changes (git checkout -- those files), or git stash those files.
git branch --merged
shows that this branch already has the commits of which other branches
git branch --no-merged
git branch -m <new_branch_name>
changes (or moves) the currently checked-out branch to a new name.
CAUTION: may cause extra workarounds when other users are already working on the old name of branch.
git branch -d <branch_to_delete>
First, checkout to another branch before deleting this branch. This command will complain if the changes are not merged in any other branch (-D to force delete).
Returns the HEAD commit-id of the deleted branch.
export PS1='\w $(tput setaf 3)$(__git_ps1 "(%s)") $(tput sgr0)> '
__git_ps1 is a fuction provided by git-prompt.sh file which can be found at github.com/git
git-completion.bash file can also be installed similarly.
First, you must create your branch locally
git checkout -b your_branch
After that, you can work locally in your branch. When you are ready to share the branch, push it. The next command pushes the branch to the remote repository origin and tracks it.
git push -u origin your_branch
Teammates can reach your branch by doing:
git fetch
git chekcout origin/your_branch
You can continue working in the branch and pushing whenever you want without passing arguments to git push (argument-less git push will push the local master to remote master, local your_branch to remote your_branch, etc.)
stackoverflow: how-do-i-create-a-remote-git-branch
bash \r not foundChange git core autocrlf to input and re-clone the repo.
stackoverflow: env-bash-r-no-such-file-or-directory
If the project is cloned on linux (LF) server and we open it to edit in VSCode on Windows (CRLF), then we might do -
git config --global core.autocrlf true
in both git bash (Windows) and on linux build server.
If you want to know what file this config is saved in, you can run the command: git config --global --edit
stackoverflow: how-to-change-line-ending-settings
git fetch origin pull/<PR_ID>/head:<new_branch_name>
Then checkout to new_branch_name
stackoverflow: how-can-i-check-out-a-github-pull-request-with-git
git push -u origin <new_branch_name>
Problem:
There is a new repo B and an old repo A. I want to have all commits from A into B preserving the commit history (git log should show me commit history)
Solution:
- Go into B (‘git clone git@github.com: devpogi/B.git)
-git checkout Bnewbranchname
- Add remote for repo A (git remote add repAorigin git@github.com:devpogi/A.git)
-git fetch repoAorigin
-git merge repoAorigin/master –allow-unrelated-histories
- Might introduce a merge conflict
- Resolve the conflict and make a commit
-git push`
stackoverflow: moving-git-repository-content-to-another-repository-preserving-history
stackoverflow: how-to-handle-fix-git-add-add-conflicts
git patchIf you haven’t yet committed the changed, then:
git diff > mychanges.patch
But it might be possible that there are several untracked (new) files which won’t be in your git diff output. So, one way to do a patch is to stage everything for a new commit (git add each file, or just git add .) but don’t do the commit yet, and then run:
git diff --cached > mychanges.patch
You can later apply the patch as:
git paply mychanges.patch
blogpost: create-a-git-patch-from-the-uncommitted-changes-in-the-current-working-directory
If you need to send the patch file via mail, there is a better built-in way to do this in git using git format-patch command.
The patch file generated will include subject, author, etc, additional information traditionally used in UNIX-like mail-patching.
If you need top n commits from a specific commit-sha in the patch file - git format-patch -n commit-sha
example -
git
git format-patch -1 HEAD
This will generate a file like 0001-commit-message.patch
To apply this patch, use a series of steps -
- git apply --stat 0001-commit-message.patch (shows stats)
- git apply --check 0001-commit-message.patch (checks for error before applying)
- git am < 0001-commit-message.patch (applies the patch, you will see the commit appear in git log)