Reasonable Defaults

If you have a terminal open in my_project/, and you rename that folder in another window, Bash won't tell you. It will keep showing my_project/ in your prompt. If you edit files or git commit, you are silently working inside the newly renamed folder. This makes it look like your work vanished when you try to find it later.

This script hooks into Bash's PROMPT_COMMAND to check if your logical path matches physical reality every time you press enter. If the ground shifts beneath your feet, it drops a wall of doom so you know exactly where your files actually are.

 ============================================================ 
                 WARNING: GHOST SHELL DETECTED                
 ============================================================ 
 Your logical path no longer matches physical reality.
 Bash thinks you are in: /home/user/GHOST_DIRECTORY
 The directory was actually renamed to: /home/user/SHADOW_WORLD
 (Warning 1 of 3. Muting after limit reached.)

Installation

1. Open your bash config:

nano ~/.bashrc

2. Paste this at the very bottom:

# Set how many times you want the red warning before it leaves you alone
export GHOST_SHELL_MAX_WARNINGS=3

# Internal state variables
export _GHOST_SHELL_COUNT=0
export _GHOST_LAST_PWD=""

check_ghost_shell() {
    local logical_pwd="$PWD"
    local physical_pwd="$(pwd -P 2>/dev/null)"

    # If the directory was deleted completely, pwd -P fails
    if [[ -z "$physical_pwd" ]]; then
        physical_pwd="[DELETED]"
    fi

    # If physical matches logical, we are in reality. Reset the counter.
    if [[ "$logical_pwd" == "$physical_pwd" ]]; then
        _GHOST_SHELL_COUNT=0
        _GHOST_LAST_PWD="$logical_pwd"
        return
    fi

    # If the user changed to a DIFFERENT ghost shell, reset the counter
    if [[ "$_GHOST_LAST_PWD" != "$logical_pwd" ]]; then
         _GHOST_SHELL_COUNT=0
         _GHOST_LAST_PWD="$logical_pwd"
    fi

    # If we are under the max warning limit, throw the red wall of doom
    if (( _GHOST_SHELL_COUNT < GHOST_SHELL_MAX_WARNINGS )); then
        echo -e "\n\e[1;41;97m ============================================================ \e[0m"
        echo -e "\e[1;41;97m                 WARNING: GHOST SHELL DETECTED                \e[0m"
        echo -e "\e[1;41;97m ============================================================ \e[0m"
        echo -e "\e[1;31m Your logical path no longer matches physical reality.\e[0m"
        echo -e "\e[1;31m Bash thinks you are in: $logical_pwd\e[0m"

        if [[ "$physical_pwd" == "[DELETED]" ]]; then
            echo -e "\e[1;31m The directory you are standing in has been DELETED.\e[0m"
        else
            echo -e "\e[1;31m The directory was actually renamed to: $physical_pwd\e[0m"
        fi

        echo -e "\e[1;31m (Warning $((_GHOST_SHELL_COUNT + 1)) of $GHOST_SHELL_MAX_WARNINGS. Muting after limit reached.)\e[0m\n"

        ((_GHOST_SHELL_COUNT++))
    fi
}

# Attach our patch to the Bash prompt hook safely
if [[ "$PROMPT_COMMAND" != *"check_ghost_shell"* ]]; then
    PROMPT_COMMAND="check_ghost_shell; $PROMPT_COMMAND"
fi

3. Reload your config:

source ~/.bashrc

Configuration

Change export GHOST_SHELL_MAX_WARNINGS=3 to whatever number you want. It will warn you X times before shutting up so you can continue working in the void if you really want to.