Local history per project in bash

bash_local_history.sh

# Local history per project
# Default history file
export __LOCALHISTORY_DEFAULT="$HOME/.bash_history"
# Current history file
export __LOCALHISTORY="$__LOCALHISTORY_DEFAULT"
# Variable displaying path of new history file after changing directory or updating file
export __LOCALHISTORY_DISPLAY_PATH=""
# Symbol shown if the local history is active
export __LOCALHISTORY_ACTIVE=""
# Status that is displayed
export __LOCALHISTORY_STATUS=""
# Find history file
__localhistory() {
    local __LOCALHISTORY_TRAVERSAL="$(__localhistory_realpath "$1")"
    # Is there a writable bash history file here?
    if [ -w "$(__localhistory_realpath "$__LOCALHISTORY_TRAVERSAL/.local_bash_history")" ]; then
        # Only set and display if new history file is found
        __localhistory_update "$__LOCALHISTORY_TRAVERSAL/.local_bash_history"
    elif [ "$__LOCALHISTORY_TRAVERSAL" != "/" ]; then
        # Try traversing up to look again if we aren't already in root
        __localhistory "$__LOCALHISTORY_TRAVERSAL/.."
    else
        # Fallback to home directory
        __localhistory_update "$__LOCALHISTORY_DEFAULT"
    fi
}
# Update the history file
__localhistory_update() {
    # $1 is the file
    if [ "$__LOCALHISTORY" != "$(__localhistory_realpath "$1")" ]; then
        # Write last history file
        history -a
        # Clear loaded history so history can be replaced
        history -c
        __LOCALHISTORY="$(__localhistory_realpath "$1")"
        HISTFILE="$__LOCALHISTORY"
        export __LOCALHISTORY_DISPLAY_PATH="$1 "
        # Read history
        history -r;
    else
        export __LOCALHISTORY_DISPLAY_PATH=""
    fi
    # Active symbol
    if [ "$__LOCALHISTORY" != "$__LOCALHISTORY_DEFAULT" ]; then
        export __LOCALHISTORY_ACTIVE="% "
    fi
    # Disable active symbol if path shown
    if [ "$__LOCALHISTORY_DISPLAY_PATH" != "" ]; then
        export __LOCALHISTORY_ACTIVE=""
    fi
    # Combination of those
    export __LOCALHISTORY_STATUS="$__LOCALHISTORY_DISPLAY_PATH$__LOCALHISTORY_ACTIVE"
}
# Used for paths with spaces in name
__localhistory_realpath() {
    realpath "$@"
}