remove shell scripts as "," command and auto rebuild

The "go build" is fast but sticky when hit "," command, so I remove it.
I think auto rebuild is not that useful, just fancy.

main.go

@@ -1,29 +1,10 @@
 package main
 
 import (
-	"errors"
 	"fmt"
 	"os"
 )
 
-var commaSh = `#!/bin/sh
-
-script_path=$(realpath $0)
-script_dir=$(dirname $script_path)
-
-cd $script_dir
-
-output=/tmp/commandgo
-
-# why not just using "go run ." ?
-# Because "go run ." will inject GOBIN into PATH while compiling,
-# and modifed PATH will pass into actual program.
-# So the program doesn't have the same PATH as outside.
-# It's not a acceptable behavior.
-
-go build -o $output . && $output $@
-`
-
 func commandsUsage() string {
 	return fmt.Sprintf(
 		`commands:
@@ -32,18 +13,6 @@ func commandsUsage() string {
 }
 
 func main() {
-	pwd, err := os.Getwd()
-	if err != nil {
-		panic(fmt.Errorf("detect current directory failed! %w", err))
-	}
-	target := pwd + string(os.PathSeparator) + ","
-	_, err = os.Stat(target)
-	if errors.Is(err, os.ErrNotExist) {
-		err := os.WriteFile(target, []byte(commaSh), 0755)
-		if err != nil {
-			panic(fmt.Errorf("write sh failed: %w", err))
-		}
-	}
 	if len(os.Args) >= 2 {
 		switch os.Args[1] {
 		case "path":