Why when using the "env -i" command the environment is not really empty?
When you use the `env -i` command, it indeed creates a new environment with very few environment variables, but it doesn't make the environment completely empty for a few reasons: 1. **Essential Variables:** Certain environment variables are essential for the proper functioning of the shell and the system. For example, variables like `PATH` and `HOME` are necessary for the shell to locate executable programs and to determine the user's home directory. Removing these could render the environment unusable. 2. **Shell-Specific Variables:** The shell you're using (e.g., Bash, Zsh, etc.) may have its own environment variables that are set upon starting a shell session, and these are not removed by `env -i`. For instance, `PS1` (the shell prompt), `SHELL` (path to the current shell), and `TERM` (the terminal type) are typically set by the shell and may persist. So, while `env -i` clears many environment variables, it retains some essential ones and those that are shell-specific