Adding command-line hint error message on bad arguments/flags

main.go

@@ -58,16 +58,14 @@ func main() {
 			}
 			fmt.Fprintf(os.Stderr, "\ntry:\n\n  go install -tags %s github.com/xo/usql@%s\n\n", tag, rev)
 		}
-		/*
-			switch estr := err.Error(); {
-			case err == text.ErrWrongNumberOfArguments,
-				strings.HasPrefix(estr, "unknown flag:"),
-				strings.HasPrefix(estr, "unknown shorthand flag:"),
-				strings.HasPrefix(estr, "bad flag syntax:"),
-				strings.HasPrefix(estr, "flag needs an argument:"):
-				metacmd.Usage(os.Stderr, false)
-			}
-		*/
+		switch estr := err.Error(); {
+		case err == text.ErrWrongNumberOfArguments,
+			strings.HasPrefix(estr, "unknown flag:"),
+			strings.HasPrefix(estr, "unknown shorthand flag:"),
+			strings.HasPrefix(estr, "bad flag syntax:"),
+			strings.HasPrefix(estr, "flag needs an argument:"):
+			fmt.Fprintln(os.Stderr, text.CommandHelpHint)
+		}
 		os.Exit(1)
 	}
 }

text/text.go

@@ -18,6 +18,7 @@ var (
 	PassfileName          = CommandName + `pass`
 	ConfigName            = "config"
 	Banner                = `the universal command-line interface for SQL databases`
+	CommandHelpHint       = `hint: try "` + CommandName + ` --help" for more information.`
 	NotConnected          = `(not connected)`
 	HelpPrefix            = `help`
 	QuitPrefix            = `quit`