os模块
os模块的作用：
os，语义为操作系统，所以肯定就是操作系统相关的功能了，可以处理文件和目录这些我们日常手动需要做的操作，就比如说：显示当前目录下所有文件/删除某个文件/获取文件大小……
另外，os模块不受平台限制，也就是说：当我们要在linux中显示当前路径时就要用到pwd命令，而Windows中cmd命令行下就要用到这个，额...我擦，我还真不知道，（甭管怎么着，肯定不是pwd），这时候我们使用python中os模块的os.path.abspath(name)功能，甭管是linux或者Windows都可以获取当前的绝对路径。
os模块的常用功能：
1 os.name #显示当前使用的平台
>>> os.name
‘nt‘ #这表示Windows
>>> os.name
‘posix‘ #这表示Linux
2 os.getcwd() #显示当前python脚本工作路径
>>> os.getcwd()
‘C:\\Users\\Capital-D\\PycharmProjects\\untitled‘ #使用pycharm
>>> os.getcwd()
‘/root‘ #Linux平台在/root目录直接使用python3命令
3 os.listdir(‘dirname‘) #返回指定目录下的所有文件和目录名
#相对于os.getcwd路径下的文件
>>> os.listdir()
[‘.idea‘, ‘test‘]
>>> os.listdir()
[‘.bash_logout‘, ‘Python-3.4.4‘, ‘.mysql_history‘, ‘.tcshrc‘, ‘Python-3.4.4.tar.xz‘, ‘.bash_profile‘, ‘.lesshst‘, ‘install.log.syslog‘, ‘.cshrc‘, ‘04.sql‘, ‘anaconda-ks.cfg‘, ‘test‘, ‘.viminfo‘, ‘phpMyAdmin-4.4.15-all-languages.tar.bz2‘, ‘1test‘, ‘.bashrc‘, ‘binlog.sql‘, ‘back.sql‘, ‘install.log‘, ‘binlog4.sql‘, ‘.bash_history‘, ‘backup.sql‘, ‘text.py‘, ‘.rnd‘, ‘test1‘]
4 os.remove(‘filename‘) #删除一个文件
[root@slyoyo ~]# touch hahaha
[root@slyoyo ~]# ls
04.sql back.sql binlog.sql install.log.syslog Python-3.4.4.tar.xz text.py
1test backup.sql hahaha phpMyAdmin-4.4.15-all-languages.tar.bz2 test
anaconda-ks.cfg binlog4.sql install.log Python-3.4.4 test1
#hahaha（粉色字体）存在
[root@slyoyo ~]# python3
Python 3.4.4 (default, Apr 5 2016, 04:23:19)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.remove(‘hahaha‘)
>>> exit()
[root@slyoyo ~]# ls
04.sql anaconda-ks.cfg backup.sql binlog.sql install.log.syslog Python-3.4.4 test text.py
1test back.sql binlog4.sql install.log phpMyAdmin-4.4.15-all-languages.tar.bz2 Python-3.4.4.tar.xz test1
#hahaha已被删
5 os.makedirs(‘dirname/dirname‘) #可生成多层递规目录
[root@slyoyo ~]# ls
04.sql anaconda-ks.cfg backup.sql binlog.sql install.log.syslog Python-3.4.4 test text.py
1test back.sql binlog4.sql install.log phpMyAdmin-4.4.15-all-languages.tar.bz2 Python-3.4.4.tar.xz test1
[root@slyoyo ~]# python3
Python 3.4.4 (default, Apr 5 2016, 04:23:19)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.makedirs(‘hahaha/linghuchong‘)
>>> exit()
[root@slyoyo ~]# ls
04.sql back.sql binlog.sql install.log.syslog Python-3.4.4.tar.xz text.py
1test backup.sql hahaha phpMyAdmin-4.4.15-all-languages.tar.bz2 test
anaconda-ks.cfg binlog4.sql install.log Python-3.4.4 test1
[root@slyoyo ~]# ls hahaha/
linghuchong
[root@slyoyo ~]# ls hahaha/linghuchong/
[root@slyoyo ~]#
6 os.rmdir(‘dirname‘) #删除单级目录
[root@slyoyo ~]# ls
04.sql back.sql binlog.sql install.log.syslog Python-3.4.4.tar.xz text.py
1test backup.sql hahaha phpMyAdmin-4.4.15-all-languages.tar.bz2 test
anaconda-ks.cfg binlog4.sql install.log Python-3.4.4 test1
[root@slyoyo ~]# ls hahaha/
linghuchong
[root@slyoyo ~]# ls hahaha/linghuchong/
[root@slyoyo ~]# python3
Python 3.4.4 (default, Apr 5 2016, 04:23:19)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.rmdir(‘hahaha/linghuchong‘)
>>> exit()
[root@slyoyo ~]# ls hahaha/
[root@slyoyo ~]#
7 os.rename("oldname","newname") #重命名文件
>>> os.getcwd()
‘/root/hahaha‘
>>> os.listdir()
[‘test‘]
>>> os.rename(‘test‘,‘test_new‘)
>>> os.listdir()
[‘test_new‘]
8 os.system() #运行shell命令,注意：这里是打开一个新的shell，运行命令，当命令结束后，关闭shell
>>> os.system(‘pwd‘)
/root/hahaha
0
9 os.sep #显示当前平台下路径分隔符
>>> os.sep
‘/‘ #linux
>>> os.sep
‘\\‘ #windows
10 os.linesep #给出当前平台使用的行终止符
>>> os.linesep
‘\n‘ #linux
>>> os.linesep
‘\r\n‘ #windows
11 os.environ #获取系统环境变量
os.environ
environ({‘USERPROFILE‘: ‘C:\\Users\\Capital-D‘, ‘PROCESSOR_ARCHITECTURE‘: ‘x86‘, ‘SESSIONNAME‘: ‘Console‘, ‘UGII_BASE_DIR‘: ‘D:\\Program Files (x86)\\Siemens\\NX 8.0‘, ‘COMMONPROGRAMW6432‘: ‘C:\\Program Files\\Common Files‘, ‘COMMONPROGRAMFILES(X86)‘: ‘C:\\Program Files (x86)\\Common Files‘, ‘MOZ_PLUGIN_PATH‘: ‘C:\\Program Files (x86)\\Foxit Software\\Foxit Reader\\plugins\\‘, ‘ALLUSERSPROFILE‘: ‘C:\\ProgramData‘, ‘PYTHONIOENCODING‘: ‘UTF-8‘, ‘NUMBER_OF_PROCESSORS‘: ‘4‘, ‘APPDATA‘: ‘C:\\Users\\Capital-D\\AppData\\Roaming‘, ‘TERM‘: ‘emacs‘, ‘TEMP‘: ‘C:\\Users\\CAPITA~1\\AppData\\Local\\Temp‘, ‘PROGRAMDATA‘: ‘C:\\ProgramData‘, ‘COMSPEC‘: ‘C:\\windows\\system32\\cmd.exe‘, ‘WINDIR‘: ‘C:\\windows‘, ‘PROCESSOR_IDENTIFIER‘: ‘Intel64 Family 6 Model 58 Stepping 9, GenuineIntel‘, ‘PATHEXT‘: ‘.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC;.PY‘, ‘PATH‘: ‘C:\\ProgramData\\Oracle\\Java\\javapath;C:\\Program Files (x86)\\Common Files\\NetSarang;C:\\Program Files (x86)\\NVIDIA Corporation\\PhysX\\Common;C:\\Program Files (x86)\\Intel\\iCLS Client\\;C:\\Program Files\\Intel\\iCLS Client\\;C:\\windows\\system32;C:\\windows;C:\\windows\\System32\\Wbem;C:\\windows\\System32\\WindowsPowerShell\\v1.0\\;C:\\Program Files\\Intel\\Intel(R) Management Engine Components\\DAL;C:\\Program Files\\Intel\\Intel(R) Management Engine Components\\IPT;C:\\Program Files (x86)\\Intel\\Intel(R) Management Engine Components\\DAL;C:\\Program Files (x86)\\Intel\\Intel(R) Management Engine Components\\IPT‘, ‘UGII_ROOT_DIR‘: ‘D:\\Program Files (x86)\\Siemens\\NX 8.0\\UGII\\‘, ‘COMPUTERNAME‘: ‘IDEA-PC‘, ‘USERDOMAIN‘: ‘idea-PC‘, ‘TMP‘: ‘C:\\Users\\CAPITA~1\\AppData\\Local\\Temp‘, ‘SYSTEMROOT‘: ‘C:\\windows‘, ‘PROCESSOR_REVISION‘: ‘3a09‘, ‘FP_NO_HOST_CHECK‘: ‘NO‘, ‘PROGRAMFILES‘: ‘C:\\Program Files (x86)‘, ‘PYTHONDONTWRITEBYTECODE‘: ‘1‘, ‘LOCALAPPDATA‘: ‘C:\\Users\\Capital-D\\AppData\\Local‘, ‘PYTHONUNBUFFERED‘: ‘1‘, ‘LOGONSERVER‘: ‘\\\\IDEA-PC‘, ‘UGII_LANG‘: ‘simpl_chinese‘, ‘SYSTEMDRIVE‘: ‘C:‘, ‘PUBLIC‘: ‘C:\\Users\\Public‘, ‘HOMEPATH‘: ‘\\Users\\Capital-D‘, ‘PYTHONPATH‘: ‘C:\\Program Files (x86)\\JetBrains\\PyCharm 5.0.2\\helpers\\pydev‘, ‘USERNAME‘: ‘Capital-D‘, ‘UGS_LICENSE_SERVER‘: ‘28000@idea-pc‘, ‘USERDOMAIN_ROAMINGPROFILE‘: ‘idea-PC‘, ‘PYCHARM_HOSTED‘: ‘1‘, ‘OS‘: ‘