# Github and Hooks - SchoolOfSRE

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# Github and Hooks

## Git with Github

Till now all the operations we did were in our local repo while git also helps us in a collaborative environment. GitHub is one place on the internet where you can centrally host your git repos and collaborate with other developers.

Most of the workflow will remain the same as we discussed, with addition of couple of things:

1. Pull: to pull latest changes from github (the central) repo
2. Push: to push your changes to github repo so that it's available to all people

GitHub has written nice guides and tutorials about this and you can refer them here:

- GitHub Hello World
- Git Handbook

## Hooks

Git has another nice feature called hooks. Hooks are basically scripts which will be called when a certain event happens. Here is where hooks are located:

    spatel1-mn1:school-of-sre spatel1$ ls .git/hooks/
    applypatch-msg.sample     fsmonitor-watchman.sample pre-applypatch.sample     pre-push.sample           pre-receive.sample        update.sample
    commit-msg.sample         post-update.sample        pre-commit.sample         pre-rebase.sample         prepare-commit-msg.sample

Names are self explanatory. These hooks are useful when you want to do certain things when a certain event happens. Ie: if you want to run tests before pushing code, you would want to setup `pre-push` hooks. Let's try to create a pre commit hook.

    spatel1-mn1:school-of-sre spatel1$ echo "echo this is from pre commit hook" > .git/hooks/pre-commit
    spatel1-mn1:school-of-sre spatel1$ chmod +x .git/hooks/pre-commit

We basically create a file called `pre-commit` in hooks folder and make it executable. Now if we make a commit, we should see the message getting printed.

    spatel1-mn1:school-of-sre spatel1$ echo "sample file" > sample.txt
    spatel1-mn1:school-of-sre spatel1$ git add sample.txt
    spatel1-mn1:school-of-sre spatel1$ git commit -m "adding sample file"
    this is from pre commit hook     # <===== THE MESSAGE FROM HOOK EXECUTION
    [master 9894e05] adding sample file
    1 file changed, 1 insertion(+)
    create mode 100644 sample.txt

## What next from here?

There are a lot of git commands and features which we have not explored here. But with the base built-up, be sure to explore concepts like

- Cherrypick
- Squash
- Amend
- Stash
- Reset