Issue #21018 has been reported by nobu (Nobuyoshi Nakada). ---------------------------------------- Bug #21018: Show invalid command line option more properly https://bugs.ruby-lang.org/issues/21018 * Author: nobu (Nobuyoshi Nakada) * Status: Open * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- Currently the invalid command line option character is printed as-is. This makes the error message confusing sometimes. ```console $ ruby -$'\rx' (-h will show valid options) (RuntimeError) $ ruby -$'\U1f608' ruby: invalid option -? (-h will show valid options) (RuntimeError) ``` These are actually: ```console $ ruby -$'\rx' |& cat -e ruby: invalid option -^M (-h will show valid options) (RuntimeError)$ $ ruby -$'\U1f608' |& cat -e ruby: invalid option -M-p (-h will show valid options) (RuntimeError)$ ``` I think control characters and multibyte characters should be printed properly. -- https://bugs.ruby-lang.org/