Description

The current install.sh script blindly appends configuration to shell config files (.bashrc, .zshrc, config.fish) without checking if the configuration already exists. This causes duplicate PATH exports and environment variables every time the install script is run.

Steps to reproduce

1. Run the install script:

curl -fsSL https://github.com/owenizedd/bum/raw/main/install.sh | bash

2. Run the install script again.
3. Check your shell config file (e.g., cat ~/.bashrc).
4. Observe duplicate bum configuration entries.

Expected behaviour

The install script should only add the configuration once.

Environment

OS: Multiple (affects Linux, macOS)
Shell: bash, zsh, fish
bum version: v0.6.1