git-notes.txt

git init //this initialises an empty git repository, by making .git folder
ls -lart //shows even hidden folders


/*

    Without options, ls displays files names only. The most common options to display additional information are:

    -l long format, displaying Unix file types, permissions, number of hard links, owner, group, size, last-modified date and filename
    -F append a "/" to directory names and a "*" to executable files.
    -g display group but not owner
    -o display owner but not group (when combined with -g both group and owner are suppressed)
    -d shows information about a symbolic link or directory, rather than about the link's target or listing the contents of a directory.
    -h output sizes in human readable format. (e.g., 1K, 234M, 2G, etc.) This option is not part of the POSIX standard, although implemented in several systems, e.g., GNU coreutils in 1997,[10] FreeBSD 4.5 in 2002,[11] and Solaris 9 in 2002.[12]

Additional options controlling how files are displayed include:

    -f do not sort. Useful for directories containing large numbers of files.
    -t sort the list of files by modification time. (default is alphabetically)
    -1 (one) force output to be one entry per line.
    -R recursively list files in subdirectories and their subdirectories …
    --full-time to show times with seconds and milliseconds instead of down to the minute.

It is frequently possible to highlight different types of files with different colors, instead of with characters as -F would. This is an area where the two main ls versions differ:

    GNU ls uses the --color option; checks the Unix file type, the file permissions and the file extension and uses its own database to control colors maintained using dircolors.
    FreeBSD ls uses the -G option; checks only the Unix file type and file permissions. and uses the termcap database[13]

*/

git add <> // used to add files to repo and sent to staging area
git status // shows changes to be committed in green that is the staging area
            // this also tells which branch etc etc, VERY important command
git commit // this will open a place to write a commit message
git commit -m "commit message" //better
touch file.cpp //creates an empty file
touch .gitignore //is used to make gitignore file
git add -A //to stage all files
git checkout <file> //matches working files with last commit
git checkout -f //macthes all files with previous commit
git log // to check commit log
git log -p -<num> //to check log of last <num> commits
git diff //compare working tree with staging area
git diff --staged //compare working tree with staged changes
git commit -a -m "message" // this directly adds and commits , only works with tracked files(git add'd atleast once)
git rm <file> //deletes from working directory as well as staged
git rm --cached <file> //deletes only from staging area
git rm --cached -r * // remove every staged thing
git add -f <file> //can be used to forcefully add an ignored file
git status -s //summarised status, first box-green staging area, second box-red working tree, green-added to staging
            //If "MM" modified in staging area as well as working tree




#Branches are used to make another copy to work on, thus not affecting master branch

git branch <branch_name> //used to create branch
git branch //used to see all branches, current branche is highlighted by green
git checkout <branch_name> //to switch to a different branch, we can edit anything here, and later we can merge this to the master branch

#Merge command will be used to merge two branches
To merge "new" branch to "master"
1. first come to master branch
2. git merge "new"

git checkout -b <branch_name> // this makes a branch and switches to it

#Github
Github is the hosting service for git repositories
Remote repositories: we can push local repo into remote repo
git remote add origin <https://github.com/AkshatAggarwal14/test.git> //adds remote repo with name "origin"
git remote // lists all remotes
git remote -v // lists the URLs for fetch and push
git push origin master //pushes master repo to origin remote
git branch -d <branch_name> // to delete branch
git filter-branch -f --tree-filter 'rm -f <THE PATH TO GIANT FILE>' HEAD --all //to remove large files <- as file needs to be removed from commit/unpushed history

#for large files
$ git rm --cached giant_file
# Stage our giant file for removal, but leave it on disk

git commit --amend -CHEAD
# Amend the previous commit with your change
# Simply making a new commit won't work, as you need
# to remove the file from the unpushed history as well

git push
# Push our rewritten, smaller commit

if repository is not found because it was private, you might need to add SSH keys
ssh-keygen -t rsa -b 4096 -C "akshataggarwal1411@gmail.com" //this generates our key
ssh-keygen -t ed25519 -C "akshataggarwal1411@gmail.com"
// to deploy key
eval "$(ssh-agent -s)" //Agent pid XXXX //pid is process id 
ssh-add ~/.ssh/id_ed25519 //to add the identity

//now to add ssh key to github account
cat ~/.ssh/id_rsa //will show content of the key
clip < ~/.ssh/id_ed25519.pub //to copy

NOW this key can be added to your github account and provides the computer read/write access




to use SSH we can change to SSH on github and use that link as origin
git remote set-url origin git@github.com:AkshatAggarwal14/test.git //to change URL
now URLS have been changed in git remote -v 

git push -u origin master //to push

# we can checkout to other branches and push them to repo too
#if other branch has changes we get a prompt on github to compare and pull req
git push //shorthand repeats last push command where we used -u



#Git Clone
git clone <URL> //copy url from the repo to clone 
    //^ This clones into the current directory

git clone <URL> <foldername> //creates a folder inside current directory where the repo is cloned

rm -rf .git to delete the repo

if errors while pushing (because some files are in the branch but not in working tree) first pull using
git pull origin master
and then push with the changes