Hi, sorry for making these confusion. The issue just happened relatively after I did the Windows latest update (1803). The terminal worked perfect before that. I tried to reinstall the latest version of git and both stable and daily-building version of Rstudio. Nothing changes. Sorry I don't know how to provide replicated sample for this case, given this is not a problem of git or any command.
Here's the system information
RStudio Edition : Desktop
RStudio Version : 1.2.650
OS Version : x86_64-w64-mingw32/x64 (64-bit)
R Version : 3.5.0 (2018-04-23)
Applicaiton log: sorry, as a "new" user, I can't upload it here. Do you want me to attach it in the github issue?
I also posted an issue in Github, https://github.com/rstudio/rstudio/issues/2849, where you can see more information about the software environment I'm working on.