Enable command completion for git commands. Also, if current directory is under git control, update prompt to show state. Good documentation is in the comments of the downloaded scripts.

git-improvements.bash

#!/bin/bash
#
# Enable command completion for git commands. Also, if current directory is
# under git control, update prompt to show state. Good documentation is in
# the comments of the downloaded scripts below. After running this script,
# source ~/.bash_profile to see the results:
#   /bin/bash git-improvements.bash; source ~/.bash_profile
#

curl --create-dirs \
  'https://raw.githubusercontent.com/git/git/master/contrib/completion/{git-completion.bash}' \
  -o "${HOME}/.config/git/#1" \
  'https://raw.githubusercontent.com/git/git/master/contrib/completion/{git-prompt.sh}' \
  -o "${HOME}/.config/git/#1"

cat >> ${HOME}/.bash_profile << 'END';

# If current directory is under git control, update prompt to show state.
# ----------+-------------------------+-------------------------------
#   Symbols |        Meaning          |        Variable
# ----------+-------------------------+-------------------------------
#     *        Unstaged files            GIT_PS1_SHOWDIRTYSTATE=1
#     +        Staged files                "
#     $        Stashed files             GIT_PS1_SHOWSTASHSTATE=1
#     %        Untracked files           GIT_PS1_SHOWUNTRACKEDFILES=1
#     <        Upstream is ahead         GIT_PS1_SHOWUPSTREAM=auto
#     >        Upstream is behind          "
#     =        Up to date                  "
#     <>       Diverged from upstream      "
# ----------+-------------------------+-------------------------------
# Also, enable command completion for git commands.
# Good documentation is in the comments of the ~/.config/git scripts.
#
source ${HOME}/.config/git/git-prompt.sh
export GIT_PS1_SHOWDIRTYSTATE=1
export GIT_PS1_SHOWSTASHSTATE=1
export GIT_PS1_SHOWUNTRACKEDFILES=1
export GIT_PS1_SHOWUPSTREAM=auto
export GIT_PS1_SHOWCOLORHINTS=1
export PROMPT_COMMAND='__git_ps1 "\h:\W \u" "\\\$ "'
source ${HOME}/.config/git/git-completion.bash
END