change directory in bash is not affecting the post-commit hook - bash

Question

i've made the following bash script to commit the parent repo after some change in submodule.
it's all about that the script want to cd .. to check the parent repo current branch but the problem is that the cd .. is not affecting the upcoming commands because i guess the subshell
i've tried to run
1- cd ../ && before each command
2- make alias but didn't succeed
3- run exec but the script didn't continued
#!/bin/sh
#
# An example hook script to verify what is about to be committed.
# Called by "git commit" with no arguments. The hook should
# exit with non-zero status after issuing an appropriate message if
# it wants to stop the commit.
#
# To enable this hook, rename this file to "post-commit".
commit_msg= git log -1 --pretty=%B
if [[ $(git branch | grep \* | cut -d ' ' -f2) == "int1177/next" ]]; then
cd ..
if [[ $(git branch | grep \* | cut -d ' ' -f2) == "B0/next" ]]; then
git add 6_Tests
git commit -m "bs esss"
echo "development branch B0/next has now new commit"
else
echo "development branch isn't B0/next"
fi
else
echo "current branch isn't int1177/next"
fi

Answer 1

Actually, this particular problem is not a bash issue, but rather a Git issue.
Why doesn't "cd" work in a shell script? is valid in general, and is a suitable answer to many other questions. But this particular post-commit hook is trying to chdir out of a submodule into its parent superproject, then make a commit within the parent superproject. That is possible. It may be a bad idea for other reasons—in general it's unwise to have Git commit hooks create commits, even in other repositories1—but in this particular case you're running into the fact that Git finds its directories through environment variables.
In particular, there's an environment variable GIT_DIR that tells Git: The .git directory containing the repository is at this path. When Git runs a Git hook, Git typically sets $GIT_DIR to . or .git. If $GIT_DIR is not set, Git will find the .git directory by means of a directory-tree search, but if $GIT_DIR is set, Git assumes that $GIT_DIR is set correctly.
The solution is to unset GIT_DIR:
unset GIT_DIR
cd ..
The rest of the sub-shell commands will run in the one-step-up directory, and now that $GIT_DIR is no longer set, Git will search the superproject's work-tree for the .git directory for the superproject.
As an aside, this:
$(git branch | grep \* | cut -d ' ' -f2)
is a clumsy way to get the name of the current branch. Use:
git rev-parse --abbrev-ref HEAD
instead, here. (The other option is git symbolic-ref --short HEAD but that fails noisily with a detached HEAD, while you probably want the quiet result to be just the word HEAD, which the rev-parse method will produce.)
1The main danger in this case is that the superproject repository is not necessarily in any shape to handle a commit right now. Edit: or, as discovered in this comment, is not even set up to be a superproject for that submodule, yet, much less to have a submodule-updating commit added.