Abhishek S. Sharma

Posted on Jul 18, 2020

Life-saving git commands

#github #git #devops #linux

1. Life-Saving git tips

We have two branches (dev and master) and one file in both branches with one commit for implementation of below scenarios

git init

touch file.txt

write something like- these are life-saving commands

git status

git add file.txt

git commit -m “First Commit”

git log

git checkout dev

git log

Now both branches have similar commits and in exact same condition, now we learn in this document the following commands

git diff
git checkout
git commit --amend
git cherry-pick
git reset (Soft, Mix, and Hard)
git clean
git reflog
git revert
print branch's hashcode

2. Gibberish fix in the file before commit check diff

add something in file write let say- asdfdsf adsdsd ssfdsf
Check the differences

git diff

To fix this

checkout file.txt

Note- Where you use this if you mistakenly unzip a file in the working directory and want to remove all these files

3.Fix wrong commit message

Now we write next change in file.txt and add a new line - yes these tips are really helpful

git status

git add

git commit -m "wrong message"

git log

you see the wrong commit message, now fix we will fix this

git commit --amend -m "right commit message"

git log

Now, you can see right commit message from which you have replaced, basically, it is a new commit, as you can see a new hash code for this commit message. It changes git history, it is a bad practice.

4. You accidentally added a file which should be not committed

Let try this,

touch not-to-be-commit.text

git status

git add not-to-be-commit.text

git commit --amend
lets write :wq

git log

and boom it disappears

5. When you commit an in the wrong branch

git branch
there are two branches

master

dev

We committed in the master branch and move that commit in dev, Also we will be returning the master in the same status it was before this commit. The Answer is cherry-pick

Cherry-pick doesn't delete any commit, it creates a new commit based on dependent commit.

Let’s implement it

git log

Pick the hash which you want to cherry-pick and copy it

git checkout dev

git log

You will see only a commit.

git cherry-pick --copied hash--

git log

Note

You brought the commit in the dev branch, however, it will not delete that commit from the master branch. to answer this we have git reset.

There are three types of git reset:

git reset soft
git reset mix
git reset hard

Let understand this with examples

Git Reset Soft

git checkout master

git log

copy the hash which one you want to have last change

git reset --soft --copied hash--

git log

You can see you no longer have that commit, which is good that we don't want it longer.

git status

Now, you can see that there are some files in the stage area, by this command, you will not lose the work.

Git Mix

git reset -copied hash-

git log

You can see you no longer have that commit, which is good that we don't want it longer.

git status

Now, you can see that there are some files in the un-stage area, it’s on you, whatever you want to do- can add changes or delete*

Git Hard

git reset --hard -copied hashcode-

git log

git status

Boom!! Nothing is left and you are on your previous commit. New changes totally deleted!!

Bonus: You want to get rid of the leftover- untracked file

git clean -df

d- directory

f-files

#### 6. When you want to track what you have done

git reflog

7. What if mistakenly run git hard and badly want the code back

git reflog

grab and copy the hash before the reset

git checkout -copied hash-

You are in the copied hash, remember everything is hash in git (branch,commit and anything), run git log in this hash

git log

You clearly can see there are the commit we have reset earlier.

git branch backup

git branch

git checkout master

git branch

git checkout backup

Isn't reflog a lifesaver?

8. You wanna undo the commit but other people pull that changes

git revert- Git revert not delete or modify any commit, it simply creates a new commit top of those that completely undo the changes, so that history remains intact.

git log

copy the hash which you want to revert

git revert -copied hash-

Write- :wq

git log

You can see there three commits- two are untouched and we have new commit with revert. if you see the file it undid the previous changes. To see these changes run diff command-

git diff -old copied hash- -reverted has(new commit)

Remember, I said everything(branch, commit) in the git has hashcode

Lets, try this- we have three branches. You already know you have git in this directory by writing a command **git init. Now, we will be doing print the hashcodes these branches. Try and run following commands

ls -al .git
ls -la .git/refs
ls -la .git/refs/heads
cat .git/refs/heads/master
cat .git/refs/heads/dev
cat .git/refs/heads/backup

All these branches have different hashcodes

Top comments (11)

Jing Xue • Jul 18 '20

4 is not correct. git commit --amend will try to amend the last commit by adding not-to-be-commit.txt to it. So after :wq you will have effectively squashed not-to-be-commit.txt to the last commit on the branch.

To undo a file accidentally added to the index, simply do git restore --staged not-to-be-commit.txt.

Abhishek S. Sharma • Jul 18 '20 • Edited

There are many ways to do that you can simply write this :

git rm --cached not-to-be-commit.txt

And Please try this one too (The —amend command), it always works for me. I practiced each and every command and wrote here. Let me know if you have other suggestions. Thanks !!

Jing Xue • Jul 18 '20

I use --amend everyday to squash changes into the last commit. If you look into the last commit on the branch after doing git --amend, you'll see that the file you didn't want to add has become part of the commit. :-)

git rm --cached would indeed work too, however it is the "old way" of doing it. If you have a recent git version, when you run git status, it would suggest to use git restore --staged.