The OS module in Python

Python file system features: OS module

1.os Module Method Classification

(1) Catalogue:

    ChDir ()         Change working directory    chroot ()        sets the root directory of the current process    Listdir ()       lists all filenames under the specified directory    mkdir ()         creates the specified directory    Makedirs ()      Create a multilevel directory    GETCWD () to return the        current working directory    rmdir ()         Delete the specified directory    removedirs ()    Delete the multilevel directory

(2) Documents:

    Mkinfo ()        Create Pipeline    mknod ()         Create device file Remove    ()        Delete file    unlink ()        Delete link file    rename ()        Rename    stat ()          returns file status information    symlink ()       create symbolic Link    utime () update timestamp    tmpfile ()       Create and open (W+B) a new temporary file

(3) Access rights

    Access (path, mode)      determines whether the specified user has access rights      os.access ('/tmp ', 0)   UID 0 user has access to/tmp directory    chmod (Path,mode        ) Modify Permissions        os.chmod ('/tmp/s ', 0640) modify/TMP/S permissions to 640    chown (path,uid,gid)     modify owner, genus Group      umask ()                 Set default permission mode        Os.umask (022)

(4) Equipment files

    Makedev ()       Create device    major ()         specify device get master device number    minor ()         specify device get secondary device number

(5) File descriptor

    Open () Lower IO opens read () Lower IO    reads write    ()         Lower IO Write 4, 5 relative less supplement:    Os.walk ()   equivalent to tree command    >>> import os    >>> a1 = Os.walk ('/root ')    >>> a1.next ()    ('/root ',     ['. Subversion ', '. ssh ', '. Ipython ', '. PKI ', '. Cache '],     [' test.py ',      '. Bash_history ',      '. CSHRC ',      '. Bash_logout ',      '. TCSHRC ',      '. Bash_profile ',      '. Mysql_history ',      '. BASHRC ',      '. Viminfo '])    returns a tuple consisting of (file name, [folder],[file])

The path module in the 2.os module

1) associated with file path

    basename ()      path base name    dirname ()       path directory name    join ()          consolidated filename    split ()         returns DirName (), basename () tuple    Splitext ()      return (filename,extension) tuple        Example:    >>> dir1 = Os.path.dirname ('/etc/sysconfig/ Iptables-config ')    >>> dir1    '/etc/sysconfig '    >>> file1 = Os.path.basename ('/etc/ Sysconfig/iptables-config ')    >>> file1    ' iptables-config '    >>> os.path.join (Dir1, file1)     '/etc/sysconfig/iptables-config '    >>> for filename in Os.listdir ('/tmp '):            print Os.path.join ('/tmp ', filename)

2) Information

    Getatime ()      returns file last accessed time    getmtime () returns file last      modified    getctime ()      returns the last time the file was changed    GetSize ( )       returns the size of the file

3) Query

    Exists () determines whether        the specified file exists    isabs ()         determines whether the specified path is an absolute path    isdir ()         Whether the directory Isfile (    ) is a file Islink () Whether the        symbolic link    ismount () is a       mount point    sanefile (F1,F2) Two paths point to the same file        example: Determine if the file exists, open it, Allow users to repeatedly enter multiple rows of data through the keyboard, append to save this file    >>> import os     >>> import os.path    >>> if Os.path.isfile ('/tmp/s '):            f1 = open ('/tmp/s ', ' A + ') while        True:            a2 = raw_input ("Input >>")            If a2 = = ' Q ' or a2 = = ' Quit ': Break            f1.write (a2+ ' \ n ')        F1.close ()

4) Object Persistent storage

 The process of changing a variable from memory to a storage or transfer is called serialization Pickle, Marshal, dbm interface, shelve module pickle persisting memory objects stored in file >>> import pickle >>> Dict1 = {' x ': 1, ' Y ': 2, ' z ': ' Hello World '} >>> f1 = open ('/t    Mp/s ', ' A + ') >>> pickle.dump (DICT1,F1) Save the dictionary in a file by passing through it >>> F1.close () # file/tmp/s     /TMP/S: ASCII Text # cat/tmp/s (dp0 s ' y ' p1 I2 ss ' x ' p2 I1 ss ' z ' P3 s ' Hello World ' P4     S. >>> F2 = open ('/tmp/s ', ' A + ') >>> dict2 = pickle.load (f2) Reload >>> dict2 {' X ': 1, ' Y ': 2, ' z ': ' Hello World '