Small README update

Updates README to cover new location change and adds one small comment to clarify a variable

README.md

@@ -96,9 +96,11 @@ Options:
 
 #### Install location
 
-The default install location for Linux is `/opt/kohya_ss`. If /opt is not writeable, the fallback is `$HOME/kohya_ss`. Lastly, if all else fails it will simply install to the current folder you are in.
+The default install location for Linux is where the script is located if a previous installation is detected that location.
+Otherwise, it will fall to `/opt/kohya_ss`. If /opt is not writeable, the fallback is `$HOME/kohya_ss`. Lastly, if all else fails it will simply install to the current folder you are in (PWD).
 
-On macOS and other non-Linux machines, it will default install to `$HOME/kohya_ss` followed by where you're currently at if there's no access to $HOME.
+On macOS and other non-Linux machines, it will first try to detect an install where the script is run from and then run setup there if that's detected. 
+If a previous install isn't found at that location, then it will default install to `$HOME/kohya_ss` followed by where you're currently at if there's no access to $HOME.
 You can override this behavior by specifying an install directory with the -d option.
 
 If you are using the interactive mode, our default values for the accelerate config screen after running the script answer "This machine", "None", "No" for the remaining questions.

setup.sh

@@ -46,6 +46,7 @@ if env_var_exists RUNPOD_POD_ID || env_var_exists RUNPOD_API_KEY; then
   RUNPOD=true
 fi
 
+# This gets the directory the script is run from so pathing can work relative to the script where needed.
 SCRIPT_DIR="$(cd -- $(dirname -- "$0") && pwd)"
 
 # Variables defined before the getopts loop, so we have sane default values.