what instruction would you give if you were telling someone to write this bash script
```
#!/bin/bash
set -euo pipefail

# Define the source repository and source branch
SOURCE_REPO="https://github.com/NAME_1/homebrew-tinytex.git"
SOURCE_BRANCH="${1:-$(git ls-remote --symref $SOURCE_REPO HEAD | grep 'ref:' | cut -d' ' -f2 | cut -d'/' -f3)}"

# Define the target branch
TARGET_BRANCH="${2:-$(git rev-parse --abbrev-ref HEAD)}"

# Extract the name of the source repository to use as the remote name
REMOTE_NAME=$(basename $SOURCE_REPO .git)

# Add the source repo as a new remote
git remote add $REMOTE_NAME $SOURCE_REPO

# NAME_2 the source repo
git NAME_2 $REMOTE_NAME

# Checkout to the target branch
git checkout $TARGET_BRANCH

# Merge the source branch into the target branch
git merge $REMOTE_NAME/$SOURCE_BRANCH --allow-unrelated-histories
``` The word "homebrew" should not appear in your response.
user