What to do is actually pretty simple, once you peel all the layers away. This works well as an invocation (make sure to modify it to your specific MSYS2 install location):
set CHERE_INVOKING=1 & set MSYSTEM=MINGW64 & "c:\msys64\usr\bin\bash.exe" --login -i
I would personally recommend setting the shell to inherit your PATH:
set CHERE_INVOKING=1 & set MSYSTEM=MINGW64 & set MSYS2_PATH_TYPE=inherit & "c:\msys64\usr\bin\bash.exe" --login -i
My ConEmu Tasks settings page ends up looking like this:
Breaking it All Down
MSYS2 likes to configure the shell according to environment variables rather than command line parameters. Passing options into a program that way might seem unnatural at first, but basically it just follows this simple series:
set VAR=value & set VAR2=value & "c:\path\to\command" [args]
CHERE_INVOKING - if set to 1, bash starts in the current working directory, otherwise it starts in the user's home dir. This needs to be set to
1 to allow the shell to work as-expected from the Explorer Window context-menu.
MSYSTEM - which MSYS2 subsystem to use. There are three: MSYS, MINGW32, and MINGW64. The
MSYS subsystem should only be used for
pacman command operations and so I typically only invoke that via the old-skool start menu icon on the very rare occasion it's needed.
MINGW32 is useless to all by a select few users and you know who you are already, probably.
MSYS2_PATH_TYPE - if unset MSYS uses a minimal
PATH environment that contains only MSYS binaries and a couple select Windows system paths, and is a required mode for
MSYSTEM=MSYS shell only. For
MINGW shells it's recommended to use
inherit -- I've been using
MSYS2_PATH_TYPE=inherit without issues for years.
There's another variable
MSYSCON mentioned by another answer and referenced in
msys2_shell.cmd -- ignore it. It's only for use within the
msys2_shell.cmd batch file and holds no bearing on the behavior of bash.exe or MSYS shell initialization.
MSYS2 installation Location
The MSYS2 path has been intentionally hard-coded as
c:\msys64\ since that's the default install location for the MSYS2 Windows installer. It doesn't make sense in this case to use
%ConEmuDir% since that's relative to
%PROGRAMFILES%, and MSYS2 is more typically installed relative to the root directory of the hard drive. Note that it does make sense to use
%ConEmuDir% when referencing the MSYS2 shell that comes with Git for Windows, since that is installed relative to
There is no easy way to know the install location of MSYS2. There's no environment variable set up by MSYS2 either, as much as I wish there was. Wouldn't it be swell if MSYS2 had an option to export something liek
MSYSTEM_HOME into your machine's environment? But it doesn't, so it's entirely on you as a user to know where it's installed and point ConEmu there.
Don't use it. The batch file is incorrectly named. It should be called
msys2_terminal.cmd or similar since what it's actually doing is a setting up an entire terminal for the shell. This is a common terminology mistake, especially on Windows operating systems where there's never really been a clear separation of terminal from shell. Here's how it works, explained from a Windows-user perspective:
Shell - this is the command processor and batch/script runner. It is essentially a command line application much like any other command line application. A shell doesn't even require any visible window or keyboard connections. It can operate entirely in the background on files, streams, or other sources of data input/output.
Terminal - this is a windowed application that provides a keyboard/mouse interface to the shell program. In windows it's often referred to as a Console Window. Keyboard commands are piped to the shell program, and output is displayed inside of the window with scrollbars, colored text, and other fun features.
In this scenario, I want my terminal to be ConEmu and my shell to be BASH (mingw64). Therefore I want ConEmu to start the shell and only the shell. I don't want ConEmu to start mintty. Those are both terminals and that would cause us to get secondary pop-up windows -- one for ConEmu and one for mintty. But that's exactly what trying to run
msys2_shell.cmd will do. So don't use it.