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GIT:
How to unfuck
Use GIT on the command line – useful hints
and how to undo common mistakes
https://www.flickr.com/photos/kalexanderson/5421517469/
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If you already know something, don’t feel bored
– something new will come along!
If you are a beginner, don’t try to understand everything
– slides are online and can be used as cheat sheets
Personal style and experience, real life examples
– there’s more than one way to do things
Disclaimer
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About Melanie
2011
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“The command line is the only place
you can run all Git commands.”
https://git-scm.com/book/en/v2/Getting-Started-The-Command-Line
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Git 101
git push
git commit
git add
git pull
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Git 101
git push
git commit
git add
git pull
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Git 101
git push
git commit
git add
git pull
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Git 101
git push
git commit
git add
git pull
Local repository
Stage
Workspace
Remote repository
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Git basics
Local repository
Stage
Workspace
Remote repository
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Just looking around
git diff
git diff HEAD
git diff origin
git diff --staged
git diff
Local repository
Stage
Workspace
Remote repository
-w ==
--ignore-all-space
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Git 101
git push
git commit
git add
git pull
Local repository
Stage
Workspace
Remote repository
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12
What is a commit, actually?
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Git push fails, git pull results in conflicts
git push
git commit
git add
Local repository
Stage
Workspace
Remote repository
git pull
git mergetool
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Stashes
git stash
git push
git commit
git add
Local repository
Stage
Workspace
Remote repository
git stash pop git stash
Stash
git pull
-u ==
--include-untracked
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Branches
git branch
itty-feature
big-feature
* master
HEAD
-a == all
-r == remote
--merged
time
commit
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Switching between branches
git checkout git checkout -
* itty-feature
big-feature
master
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A new branch
git checkout -b git merge master
itty-feature
* big-feature
master
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Going back in time
itty-feature
big-feature
* master
git checkout
git checkout HEAD
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History
git log
--graph
--oneline
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Don‘t lose your HEAD
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references the commit
1 before HEAD
references to the 1st parent
of HEAD
history of movement of HEAD,
can be seen in git reflog
reattach HEAD to tip of branch
Don’t lose your HEAD
git checkout HEAD~1
git checkout HEAD^1
git checkout HEAD@{1}
git checkout
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Reflog is your friend
git reflog
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Moving the HEAD around
git reset --hard HEAD@{1}
git reset --soft HEAD@{1}
removes one commit and all work
– all uncommitted changes are lost forever
undoes one commit and puts the work from that
commit back in the workspace
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When you
fucked up…
Keep calm and get help
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Started working in master
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Started working in master
git stash
git checkout
git stash pop
git commit –a
git push
or create a new one with “-b”, then you don’t
need to stash
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Retrieving stash causes conflicts
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Retrieving stash causes conflicts
git stash pop
git reset --soft HEAD
if there are conflicts when you run
“git stash pop”, Git will not drop the stash
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Stash is super old
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Stash is super old
git stash list
git stash show -p stash@{5}
git stash branch stash@{5}
shows content of stash
creates a new branch from the commit where
stash was created, checks it out and retrieves
the stash
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Typo in branch name
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Typo in branch name
git branch –m rename branch
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Staged a file, but it needs to be ignored
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Staged a file, but it needs to be ignored
git rm --staged removes file from tracking but leaves the file
untouched on disk
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Typo in commit message
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Typo in commit message
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Typo in commit message
git commit --amend changes the last commit message
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Forgot to commit a file
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Forgot to commit a file
git add
git commit --amend uses the previous commit message
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Undo all this amending
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Undo all this amending
git reset --soft HEAD@{1}
git commit –C HEAD@{1} -C: reuse log message, author, timestamp
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Delete the branch
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Delete the branch
git branch –d
git branch –D
git push origin :
delete branch
force delete branch. Like rm -rf
also remote
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Intermission
Coffee break for your brain
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Committed broken code and pushed it
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Committed broken code and pushed it
git revert
git commit
Creates a new commit that's the inverse of the
given hash.
Anything removed in the old commit will be
added in the new commit.
Anything added in the old commit will be
removed in the new commit.
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Committed and pushed to wrong branch
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Committed and pushed to wrong branch
git checkout
git reset --soft HEAD^
git stash
git checkout
git stash pop
git commit
git push origin
git checkout
git push --force origin
make sure you’re in the wrong branch
reset the branch back one commit
you will need to rewrite the message
force push commit deletion to original branch
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Committed in detached HEAD
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Committed in detached HEAD
git checkout -b
git merge origin
now you can push like in any other branch
adds current state of branch to latest changes
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Don’t want to deal with merge conflicts now
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Don’t want to deal with merge conflicts now
git merge --abort undo the merge and already resolved conflicts,
so you go back to your last commit
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Need files from another branch
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Need files from another branch
git checkout --
git checkout -- /*
copy file without merging
copy all files in folder
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Need a single commit from another branch
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Need a single commit from another branch
git checkout
git log
git checkout
git cherry-pick
returns list of commit hashes and messages
apply the changes introduced by this commit
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Need changes from another branch,
but must not commit them
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Need changes from another branch,
but must not commit them
git merge
git reflog
git reset --soft
git add -p
go back before the merge, but keep changes in
workspace
only commit your changes using patch mode
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Don’t want to commit all changes in one file
git add -p
Stage this hunk [y,n,q,a,d,/,j,J,g,e,?]?
patch mode
y - yes, stage this hunk
n - no, do not stage this hunk
? - print help
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Accidentally used hard reset,
last commit is gone
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Accidentally used hard reset,
last commit is gone
https://philna.sh/blog/2017/01/04/git-back-to-the-future/
git reflog
git reset --hard
shows moving to HEAD~1 plus last commit
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Someone named branch like an existing file
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Someone named branch like an existing file
git checkout
git checkout --
will checkout the file
will checkout the branch
“--” makes clear that the part is a branch,
everything after “--” must be a file path
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Danger Zone
Changing history
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Committed and pushed a password
Changing history
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Committed and pushed a password
git filter-branch --force --index-filter
'git rm --staged --ignore-unmatch ’
--prune-empty --tag-name-filter cat -- --all
echo "" >> .gitignore
git commit -a
git push --force --all --v --dry-run
git push --force --all
git push --force --tags
git for-each-ref --format='delete %(refname)'
refs/original | git update-ref --stdin
git reflog expire --expire=now --all
git gc --prune=now
removes specified file, as well as any empty commits as a
result, overwrites existing tags
add file to .gitignore
try it out first
collaborators need to rebase or check out anew
remove dangling commits
(after you’re sure everything still works)
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Committed and pushed a password
Nuclear option
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Committed and pushed a password
Nuclear option
rm
rm -rf .git/
delete repository and create a new one
git init
git commit .
git remote add origin
git push
remove all Git info from your code
manually on GitHub / Bitbucket / Gitlab etc.
push code to a new repository
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My Git history is different from the one I pulled
git fetch origin
git rebase origin/master
git stash
git fetch origin
git reset --hard origin/master
git stash pop
delete folder and clone again
when someone else changed the history
when you have local changes you want to keep
when you prefer a clean slate
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Configs
Have it your way
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Bash prompt
.bash_profile
function parse_git_dirty {
[[ $(git status 2> /dev/null | tail -n1) != "nothing to commit, working directory clean" ]] && echo "*”
}
function parse_git_branch {
git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e "s/* \(.*\)/[\1$ (parse_git_dirty)]/”
}
export PS1='\u@\h \[\033[1;33m\]\w\[\033[0m\]$(parse_git_branch)$ '
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Autocomplete Git
.bash_profile
curl http://git.io/vfhol > ~/.git-completion.bash
&& echo '[ -f ~/.git-completion.bash ] && . ~/.git-completion.bash'
>> ~/.bash_profile
Tab
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ZSH prompt
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Configs
git config --global ...
core.excludesfile ~/.gitignore_global
core.editor “atom --wait”
merge.tool meld
commit.template ~/.gitmessage.txt
help.autocorrect 50
global gitignore, e.g., “.DS_Store” or “.idea/”
set Atom as editor for commit messages
set graphical tool for “git mergetool”
set default commit message, e.g., “WEB-”
accepts typos, e.g., “git pulll” (50 == 5sec)
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Use the command line, Luke
Al says: commit early, commit often
Try not to push when you notice your error
Keep calm and almost anything can be undone
Takeaways
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[email protected]
@mgapatrick
PHP developer
Admin and Core Tools Team
Melanie G. A. PATRICK
https://speakerdeck.com/mgapatrick/git-how-to-unfuck
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