I was trying to find a solution to the annoying popup message asking for user credentials when Git is dealing with https protocol. It's pretty annoying when working with an SSH connection or even on a X-server based terminal, it's slow as I am accessing remote machines in some cases.
Basically the solution is
core.askPass config field, according to this answer you can use the following command to disable GUI based prompts and instead using Shell prompts.
git config --global core.askPass true
I am using CentOS the update for this answer in Stack Overflow suggesting that the following command will solve the issue, and it did for me!
git config --global core.askPass ""
Let me know what do you think.