Deprecate install.sh in favor of setup

Still decide to deprecate install.sh cuz TAB completion can not be done
without intrusive and automatic method, so just use ./setup instead.

install.sh

@@ -1,14 +1,10 @@
 #!/usr/bin/env bash
-# TODO: Handle TAB completion for ./setup with non-intrusive method,
-# or other shortcut helper like TUI.
-# After that, remove this script (install.sh).
-
-
-#STY_RED='\e[31m'
-#STY_RST='\e[00m'
-#printf "${STY_RED}You are using \"./install.sh\" which is kept for compatibility and will be removed in future.\n"
-#printf "Please use \"./setup install\" instead.${STY_RST}\n"
+# Remove this script (install.sh) after 2025.12.01
 
+STY_RED='\e[31m'
+STY_RST='\e[00m'
+printf "${STY_RED}You are using \"./install.sh\" which is kept for compatibility and will be removed in future.\n"
+printf "Please use \"./setup install\" instead.${STY_RST}\n"
 
 cd "$(dirname "$0")"
 ./setup install "$@"

sdata/lib/functions.sh

@@ -287,20 +287,3 @@ function check_disk_space() {
   
   return 0
 }
-
-function showhelp_global(){
-echo -e "
-
-Syntax:
-  $0 <subcommand> [OPTIONS]...
-
-Subcommands:
-      install               Idempotent installation for dotfiles.
-      exp-uninstall         Experimental uninstall
-      exp-update            Experimental update
-      help                  Show this help message
-
-Please run the following for details:
-  $0 <subcommand> -h
-"
-}

setup

@@ -10,13 +10,31 @@ prevent_sudo_or_root
 set -e
 
 #####################################################################################
+function showhelp_global(){
+printf "[$0]: Handle setup for illogical-impulse.
+
+Syntax:
+  $0 <subcommand> [OPTIONS]...
+
+Subcommands:
+  install        (Default) Install or update illogical-impulse.
+  exp-uninstall  (Experimental) Uninstall illogical-impulse.
+  exp-update     (Experimental) Update illogical-impulse without fully install.
+  help           Show this help message
+
+Please run the following for details:
+  $0 <subcommand> -h
+"
+}
 case $1 in
   # Global help
-  ""|help|--help|-h) showhelp_global;exit;;
+  help|--help|-h)showhelp_global;exit;;
   # Correct subcommand
-  install|exp-uninstall|exp-update) SCRIPT_SUBCOMMAND=$1;shift;;
+  install|exp-uninstall|exp-update)SCRIPT_SUBCOMMAND=$1;shift;;
+  # No subcommand
+  -*|"")SCRIPT_SUBCOMMAND=install;;
   # Wrong subcommand
-  *)echo "Unknown subcommand \"$1\", aborting...";exit 1;;
+  *)printf "${STY_RED}Unknown subcommand \"$1\".${STY_RST}\n";showhelp_global;exit 1;;
 esac
 #####################################################################################
 case ${SCRIPT_SUBCOMMAND} in