## 說明
有時候Centos系統默認安裝的python進入交互模式下不能使用tab快捷鍵功能，這個時候需要自己進行相關配置
---
## tab.py
```python
#!/usr/bin/env python
# python startup file
import sys
import readline
import rlcompleter
import atexit
import os
# tab completion
readline.parse_and_bind('tab: complete')
# history file
histfile = os.path.join(os.environ['HOME'], '.pythonhistory')
try:
readline.read_history_file(histfile)
except IOError:
pass
atexit.register(readline.write_history_file, histfile)
del os, histfile, readline, rlcompleter
```
---
## 配置
這里以python.27為例，把
+ 上面的tab.py 放到 /usr/lib/python2.7/site-packages/ 下面，需要先導入sys，再倒入tab模塊
+ 可以把tab.py的內容放到 `/root/.pythontab`文件中，然后在`/root/.bash_profile`中添加`export PYTHONSTARTUP=~/.pythontab`， 這種方式不需要再次導入 tab 模塊
---
## 測試
```python
root@pts/2 $ python
Python 2.7.5 (default, Sep 15 2016, 22:37:39)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> import tab
>>> sys.
sys.__class__( sys.__stdout__ sys.executable sys.path
sys.__delattr__( sys.__str__( sys.exit( sys.path_hooks
sys.__dict__ sys.__subclasshook__( sys.exitfunc( sys.path_importer_cache
```
## 附加
PYTHONSTARTUP 官網解釋：
If this is the name of a readable file, the Python commands in that file are executed before the first prompt is displayed in interactive mode. The file is executed in the same namespace where interactive commands are executed so that objects defined or imported in it can be used without qualification in the interactive session. You can also change the prompts sys.ps1 and sys.ps2 in this file.
簡單來說就是這個文件會在第一次進入交互模式的時候會被執行，所以把tab.py 加入到這個變量設定的文件中就可以達到自動導入tab.py，實現自動補全的功能
