Port python's shutil.which()

tools/utils/which.go

@@ -0,0 +1,35 @@
+// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package utils
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/sys/unix"
+)
+
+var _ = fmt.Print
+
+func Which(cmd string) string {
+	if strings.Contains(cmd, string(os.PathSeparator)) {
+		return ""
+	}
+	path := os.Getenv("PATH")
+	if path == "" {
+		return ""
+	}
+	for _, dir := range strings.Split(path, string(os.PathListSeparator)) {
+		q := filepath.Join(dir, cmd)
+		if unix.Access(q, unix.X_OK) == nil {
+			s, err := os.Stat(q)
+			if err == nil && !s.IsDir() {
+				return q
+			}
+		}
+
+	}
+	return ""
+}