• I was not able to find an open or closed issue matching what I'm seeing

Setup

• Which version of Git for Windows are you using? Is it 32-bit or 64-bit?

$ git --version --build-options

git version 2.12.2.windows.2
built from commit: 7723f38cfb0e80f010afaebdd9fec4d0822fd2e1
sizeof-long: 4
machine: x86_64

• Which version of Windows are you running? Vista, 7, 8, 10? Is it 32-bit or 64-bit?

Windows 10 64-bit LTSB

$ cmd.exe /c ver

Microsoft Windows [版本 10.0.14393]

• What options did you set as part of the installation? Or did you choose the
  defaults?

# One of the following:
> type "C:\Program Files\Git\etc\install-options.txt"
> type "C:\Program Files (x86)\Git\etc\install-options.txt"
> type "%USERPROFILE%\AppData\Local\Programs\Git\etc\install-options.txt"
$ cat /etc/install-options.txt

Path Option: Cmd
SSH Option: OpenSSH
CURL Option: OpenSSL
CRLF Option: CRLFCommitAsIs
Bash Terminal Option: MinTTY
Performance Tweaks FSCache: Enabled
Use Credential Manager: Enabled
Enable Symlinks: Disabled

• Any other interesting things about your environment that might be related
  to the issue you're seeing?

git-for-windows 2.12.2.2 32-bit works well.
git subtree command not works on 64-bit

$  git subtree pull --prefix lib/ http://172.21.73.37:3000/serial/libtc.git master
Unexpected option: pull

Details

• Which terminal/shell are you running Git from? e.g Bash/CMD/PowerShell/other

bash

• What commands did you run to trigger this issue? If you can provide a
  Minimal, Complete, and Verifiable example
  this will help us understand the issue.

#!/bin/bash

file="Neovim.zip"
echo $file | awk -F '.' '{print $1}'
nvim=$(echo $file | awk -F '.' '{print $1}')
echo "nvim=$nvim"

• What did you expect to occur after running these commands?

Should print text below

Neovim
nvim=Neovim

• What actually happened instead?

Only get text below

Neovim
nvim=

• If the problem was occurring with a specific repository, can you provide the
  URL to that repository to help us with testing?

It's not s git related issue, but in the bash of git-for-windows, and it's 64-bit only issue
On git-bash 32-bit it works fine

But on git-bash 64-bit, I get this