To show current active git branch in command prompt in linux terminal, edit ~/.bashrc

vi ~/.bashrc

Add following

show_git_branch() {
    git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/ (\1)/'
}

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]$(show_git_branch)\$ '