terminalにgitのブランチ名と作業ツリーの状態を表示する

`git push` し忘れることが多々あり、review時に変更点ないけどと3回言われ、反省:bow:して調べました。

# 前提条件
* Homebrewでgitをinstall

Homebrewでinstallしてない方は自分で「git-completion.bash」と「git-prompt.sh」をダウンロードしてください。

Homebrewでinstallした場合には下記に配置されています。

```
$ ls -al /usr/local/Cellar/git/2.11.0/etc/bash_completion.d/
total 152
drwxr-xr-x  4 a21032267  admin    136 11 30 06:06 .
drwxr-xr-x  3 a21032267  admin    102 11 30 06:06 ..
-rw-r--r--  1 a21032267  admin  60609 11 30 06:06 git-completion.bash
-rw-r--r--  1 a21032267  admin  16111 11 30 06:06 git-prompt.sh
```

多分下記で良いかと

```
$ wget https://raw.github.com/git/git/master/contrib/completion/git-completion.bash
$ wget https://raw.github.com/git/git/master/contrib/completion/git-prompt.sh
```

# 設定

基本的に`git-prompt.sh`の中身にかかれているとおりに進めれば:ok:です

```:/usr/local/Cellar/git/2.11.0/etc/bash_completion.d/git-prompt.sh
# bash/zsh git prompt support
#
# Copyright (C) 2006,2007 Shawn O. Pearce <spearce@spearce.org>
# Distributed under the GNU General Public License, version 2.0.
#
# This script allows you to see repository status in your prompt.
#
# To enable:
#
#    1) Copy this file to somewhere (e.g. ~/.git-prompt.sh).
#    2) Add the following line to your .bashrc/.zshrc:
#        source ~/.git-prompt.sh
#    3a) Change your PS1 to call __git_ps1 as
#        command-substitution:
#        Bash: PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '
#        ZSH:  setopt PROMPT_SUBST ; PS1='[%n@%m %c$(__git_ps1 " (%s)")]\$ '
#        the optional argument will be used as format string.
#    3b) Alternatively, for a slightly faster prompt, __git_ps1 can
#        be used for PROMPT_COMMAND in Bash or for precmd() in Zsh
#        with two parameters, <pre> and <post>, which are strings
#        you would put in $PS1 before and after the status string
#        generated by the git-prompt machinery.  e.g.
#        Bash: PROMPT_COMMAND='__git_ps1 "\u@\h:\w" "\\\$ "'
#          will show username, at-sign, host, colon, cwd, then
#          various status string, followed by dollar and SP, as
#          your prompt.
#        ZSH:  precmd () { __git_ps1 "%n" ":%~$ " "|%s" }
#          will show username, pipe, then various status string,
#          followed by colon, cwd, dollar and SP, as your prompt.
#        Optionally, you can supply a third argument with a printf
#        format string to finetune the output of the branch status
```
私はzshを使っているので`~/.zshrc`に以下を追加します。
Homebrewをinstallしている場合は

```
setopt PROMPT_SUBST
source /usr/local/Cellar/git/`git version | awk '{print $3}'`/etc/bash_completion.d/git-prompt.sh
source /usr/local/Cellar/git/`git version | awk '{print $3}'`/etc/bash_completion.d/git-completion.bash # deprecateと言われたらこの行をコメントアウトしてください
GIT_PS1_SHOWDIRTYSTATE=true
GIT_PS1_SHOWUNTRACKEDFILES=true
GIT_PS1_SHOWSTASHSTATE=true
GIT_PS1_SHOWUPSTREAM=auto
```
versionが変わることも考えてversionのところを`git version | awk '{print $3}'`としています

あとは`PROMPT`に設定するだけ

私の場合は下記を~/.zshrcに設定しています

```
export PROMPT="[${USER} %1~\$(__git_ps1)]%(!.#.$) "
```

# 表示サンプル

```
[USER workspace]$ cd playbook 
[USER playbook (capistrano)]$ vi README.md 
[USER playbook (capistrano *)]$ 
[USER playbook (capistrano *)]$ 
[USER playbook (capistrano *)]$ git add -i
[USER playbook (capistrano *)]$ git add -u
[USER playbook (capistrano +)]$ git commit    
[capistrano edb092a] test
 1 file changed, 1 insertion(+)
[USER playbook (capistrano)]$ 
```

肝心のpushされているかの判断が出来ていない....
hashでも表示させようか...