Issue #20874 has been reported by kyanagi (Kouhei Yanagita). ---------------------------------------- Bug #20874: Difference in documentation for `irb -U` between `man irb` and `irb --help` https://bugs.ruby-lang.org/issues/20874 * Author: kyanagi (Kouhei Yanagita) * Status: Open * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- There is a difference in documentation for `irb -U` between `man irb` and `irb --help`. * `man irb`: Same as `ruby -U' . Sets the default value for internal encodings (Encoding.default_internal) to UTF-8. * `irb --help`: Set external and internal encodings to UTF-8. Which is correct? The implementation matches that of `--help`. However, it also seems to have been implemented with the intention of behaving the same as `ruby -U`. -- https://bugs.ruby-lang.org/