Sorry for necroreply. Just to keen in history records.
When starting any program under MSYS (and MSYS2), the MSYS[2] checks whether the lunched program is linked with msys-*.dll. If program is linked with this DLL then the program expects POSIX-like environment so no path translation is performed. If program is not linked with this DLL then the program is native Windows binary, which expects native Windows paths. In such case the MSYS[2] scans all arguments for POSIX-like paths and converts all of them to Windows native paths. The problem is that all Windows drives are mounted as single letter in the root so the path like "/d/path/file" should be translated into "D:/path/file", while "/c" is translated into "C:/" To prevent this translation double slash could be used. Double slash is replaced with single slash.
Examples: ------------------------ MSYS ~ $ cmd /c echo "/c" Microsoft Windows [Version 10.0.19045.3208] (c) Microsoft Corporation. All rights reserved. C:\msys64\home\user>exit MSYS ~ $ cmd //c echo "/c" C:/ MSYS ~ $ cmd //c echo "//c" /c MSYS ~ $ cmd //c echo "///c" //c MSYS ~ $ echo.exe "/c" /c MSYS ~ $ echo.exe "//c" //c ------------------------ "echo.exe" is Msys program. cmd is not Msys program. -- Evgeny On 28.06.2021 19:29, Dietmar May via Cygwin wrote:
>/$ cmd //c echo hello />/hello />//>/which works, and this, which doesn't: />//>/$ cmd /c echo hello />//>/Microsoft Windows [Version 10.0.blah] />/(c) Microsoft Corporation. All rights reserved. />//>/C:\msys64\home\myname> /Your example seems to be inverted, the first form doesn't work, the second does with the same results you show (but inverted). It would be better if you document how you executed those commands, we're assuming a mintty terminal running a bash shell, but I haven't followed all your messages and it might be a cmd window; results shouldn't change anyway, but for completeness sake.More details for you, then:>/I just re-installed msys2 and tried a few things, with interesting result. /I install msys2-x86_64-20210604.exe (downloaded last week) from the msys2 website, and accept all defaults during installation, including the "run msys2 now" on the final installation screen (which, yes, opens a mintty terminal running msys2's bash shell). All commands are executed in that same mintty window immediately following a fresh installation.So here is the output, cut-and-pasted from that mintty terminal: dietmar@laptop MSYS ~ $ cmd //c echo hello hello dietmar@laptop MSYS ~ $ cmd /c echo hello Microsoft Windows [Version 10.0.19043.1055] (c) Microsoft Corporation. All rights reserved. C:\msys64\home\dietmar>As you can see, the first form DOES INDEED work, and the second does not. Why not try it yourself? You will likely have the same results.To find out what cmd is really doing, I believe the authoritative answer would be given by Microsoft's Command Prompt:No, wrong, cmd is getting an argument which it interprets as it seems fit, no hack there. The same applies to the ls example before, ls receives an argument which is expected to be a path, nothing strange.Microsoft Windows [Version 10.0.19043.1055] (c) Microsoft Corporation. All rights reserved. C:\Users\dietmar>cmd //c echo hello Microsoft Windows [Version 10.0.19043.1055] (c) Microsoft Corporation. All rights reserved. C:\Users\dietmar>exit C:\Users\dietmar>Here we see that cmd.exe //c starts a subshell, rather than executing a single command.However, in msys2's mintty/bash window, that same syntax works differently: dietmar@laptop MSYS ~ $ cmd //c echo hello hello dietmar@laptop MSYS ~ $ cmd ///c echo hello Microsoft Windows [Version 10.0.19043.1055] (c) Microsoft Corporation. All rights reserved. C:\msys64\home\dietmar>exit exit dietmar@laptop MSYS ~ $ cmd ////c echo hello hello dietmar@laptop MSYS ~ $ cmd //////c echo hello hello dietmar@laptop MSYS ~ $ cmd ////////c echo hello hello dietmar@laptop MSYS ~ $ cmd /////////c echo hello Microsoft Windows [Version 10.0.19043.1055] (c) Microsoft Corporation. All rights reserved. C:\msys64\home\dietmar>exit exit dietmar@laptop MSYS ~ $It seems evident that msys2 is performing slash escaping - ie. 2 consecutive slashes are consolidated into a single slash (rather like quote escaping in various languages - eg. SQL, CSV, C#, YAML) recursively (ie. repeatedly) during argument evaluation.Again, why not simply change this to a form that works without the slash hackery?dietmar@laptop MSYS ~ $ cmd /c "echo hello" hello>/Interestingly, />//>/ls //c />//>/hangs under msys2 (as well as cygwin), /Expected as the documentation link describes, //c is taken as a path to a server, you already knew that.>/whereas />//>/cmd //c />//>/does not; so it almost seems like msys2 has a hack to recognize that />/cmd.exe is being invoked ... /No, wrong, cmd is getting an argument which it interprets as it seems fit, no hack there. The same applies to the ls example before, ls receives an argument which is expected to be a path, nothing strange.>/However, both of the following also complete successfully under msys2, />/WITHOUT the double-slash hack: />//>/$ cmd /c "echo hello" />/hello />//>/$ cmd "/c" "echo hello" />/hello />//>/Both seem preferable to bad syntax. />//>/Of course, there's always the question of why libtool is using cmd.exe />/instead of /bin/echo, which seems to work just fine ... />//>/$ /bin/echo "hello world" />/hello world /-- R.Berber
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