Hi,

git aliases don’t use the user’s shell but a hardcoded /bin/sh, and this cannot be made configurable.

This, unfortunately, breaks quite some aliases and they cannot be made portable by adding something like core.sh = /bin/mksh to the .gitconfig.

I’d love if this could be made configurable.

bye, //Thorsten

On 2026-05-11 at 21:13:18, Thorsten Glaser wrote:

Yes, I believe they use `/bin/sh`, except on Windows, where they may look up things in the PATH. It is very much intentional that they use sh because it means that aliases work in a consistent way across platforms and that they work at all.

On Linux, I have mksh, but my work machine on macOS does not, so specifying `core.sh = /bin/mksh` would not work on all my systems. If you have system-level aliases as well as user-level aliases, then you need to pick a particular shell and letting the user choose will likely break the system-level aliases. This is not a hypothetical: my last company shipped system-level aliases on development VMs while users were free to customize their user-level aliases (and shell).

This will absolutely be a problem on Windows, where you have CMD, multiple versions of PowerShell, and bash, all with different syntax. Some versions of PowerShell also corrupt non-Unicode data sent through pipelines as well, which means they're effectively useless for general-purpose scripting.

It can also lead to odd behaviour on some shells because, for instance, zsh runs a config file with `-c`, `.zshenv`, that can make the shell very much less POSIX compliant, so behaviour can differ substantially from sh.

I'll also note that Git doesn't handle aliases specially. Git has a with-shell and a without-shell mode for running commands, and we use the former for aliases. We definitely do not want the with-shell mode to generically allow arbitrary shells because we cannot handle non-POSIX shells and will not quote correctly for them (almost certainly leading to security vulnerabilities). We also format the shell command as "%s \"$@\"", which also basically requires a POSIX shell to work, and we don't want to work around people's use of non-POSIX shells; that way madness lies.

However, because mksh is POSIXy, you could build Git on your system with `SHELL_PATH=/bin/mksh`, which would use `/bin/mksh` everywhere that the shell is invoked. That feature exists primarily for systems where `sh` is not POSIXy or doesn't support `local` (which I know mksh does), but there's no reason you can't use it yourself.

There has been some discussion about this issue in the past (in the context of PowerShell) at https://lore.kernel.org/git/CAAXzdLXt4+-34+OhS=Jn=-VeORN3Y2jMzzg9+bhyn88aN4hm0A@mail.gmail.com/ .

On Mon, 11 May 2026, brian m. carlson wrote:

But it could be made possible by pointing it to ~/.etc/bin/mksh on the Macintosh…

Ah, okay.

I was merely wondering that it was not configurable for aliases.

When looking at the aliases in detail, I found that I already invoked mksh -c '…' in those that used mksh-specific code, and that the one that failed merely uses a recent POSIX sh construct that /bin/sh on a customer system does not yet implement and I could reword it.

bye, //Thorsten