Issue #19384 has been reported by stringsn88keys (Thomas Powell). ---------------------------------------- Bug #19384: ASCII 128..154 characters in IO.popen or %x output do not reflect the proper encoding in Windows https://bugs.ruby-lang.org/issues/19384 * Author: stringsn88keys (Thomas Powell) * Status: Open * Priority: Normal * ruby -v: 3.1.3 * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Operating systems: Windows 10 and Windows Server 2022 (likely all recent versions of Windows) Ruby: confirmed on 2.7.7 through 3.1.3 On macOS and Linux I can create a file named "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ" and then do a directory listing via IO.popen or %x and find the file name in the output string. In Windows, while the encoding is reported as #<Encoding:UTF-8>, I have to .force_encoding on the output to be able to find the string in the output: %x|dir tmp| ----------- output encoding: #<Encoding:UTF-8> Output can be made to match by forcing the following encodings: IBM437 CP850 IBM865 IO.popen(dir tmp).read ---------------------- output encoding: #<Encoding:UTF-8> Output can be made to match by forcing the following encodings: IBM437 CP850 IBM865 But on macOS or Linux: ❯ ruby directory_test.rb %x|ls tmp| ---------- output encoding: #<Encoding:UTF-8> output matches without forcing encoding Output can be made to match by forcing the following encodings: UTF-8 UTF8-MAC CESU-8 UTF8-DoCoMo UTF8-KDDI UTF8-SoftBank IO.popen(ls tmp).read --------------------- output encoding: #<Encoding:UTF-8> output matches without forcing encoding Output can be made to match by forcing the following encodings: UTF-8 UTF8-MAC CESU-8 UTF8-DoCoMo UTF8-KDDI UTF8-SoftBank Note: The example is contrived because the actual IO.popen output is from a customer system with umlaut characters. However, I have found creating a filename with these characters will adequately reproduce the issue. Also, I'm only using ASCII/IBM437 as an encoding to create a contiguous set of characters, "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ" as a contrived example. ---Files-------------------------------- directory_test.rb (1.14 KB) -- https://bugs.ruby-lang.org/