補完

git version 2.8.3
cygwin/usr/share/bash-completion/completions/git

#    1) Copy this file to somewhere (e.g. ~/.git-completion.bash).
#    2) Add the following line to your .bashrc/.zshrc:
#        source ~/.git-completion.bash
#    3) Consider changing your PS1 to also show the current branch,
#       see git-prompt.sh for details.

以下は古い記述
http://bearmini.net/blog/View.aspx?bid=1&aid=172

Cygwin 向けのパッケージでは、必要なファイルが git-completion パッケージに含まれていますのでこれをインストールします。

自動補完を有効にする

$ vi ~/.bashrc
# Uncomment to turn on programmable completion enhancements.
# Any completions you add in ~/.bash_completion are sourced last.
[[ -f /etc/bash_completion ]] && . /etc/bash_completion

めも