how to find the target file's full(absolute path) of the symbolic link or soft link in python

问题

when i give ls -l /etc/fonts/conf.d/70-yes-bitmaps.conf

lrwxrwxrwx <snip> /etc/fonts/conf.d/70-yes-bitmaps.conf -> ../conf.avail/70-yes-bitmaps.conf

so for a symbolic link or soft link, how to find the target file's full(absolute path) in python,

If i use

os.readlink('/etc/fonts/conf.d/70-yes-bitmaps.conf')

it outputs

../conf.avail/70-yes-bitmaps.conf

but i need the absolute path not the relative path, so my desired output must be,

/etc/fonts/conf.avail/70-yes-bitmaps.conf

how to replace the .. with the actual full path of the parent directory of the symbolic link or soft link file.

回答1:

os.path.realpath(path)

os.path.realpath returns the canonical path of the specified filename, eliminating any symbolic links encountered in the path.

回答2:

As unutbu says, os.path.realpath(path) should be the right answer, returning the canonical path of the specified filename, resolving any symbolic links to their targets. But it's broken under Windows.

I've created a patch for Python 3.2 to fix this bug, and uploaded it to:

http://bugs.python.org/issue9949

It fixes the realpath() function in Python32\Lib\ntpath.py

I've also put it on my server, here:

http://www.burtonsys.com/ntpath_fix_issue9949.zip

Unfortunately, the bug is present in Python 2.x, too, and I know of no fix for it there.

回答3:

http://docs.python.org/library/os.path.html#os.path.abspath

also joinpath and normpath, depending on whether you're in the current working directory, or you're working with things elsewhere. normpath might be more direct for you.

Update:

specifically:

os.path.normpath( 
  os.path.join( 
    os.path.dirname( '/etc/fonts/conf.d/70-yes-bitmaps.conf' ), 
    os.readlink('/etc/fonts/conf.d/70-yes-bitmaps.conf') 
  ) 
)

回答4:

I recommend to use pathlib library for filesystem operations.

import pathlib

x = pathlib.Path('lol/lol/path')
x.resolve()

Documentation for Path.resolve(strict=False): make the path absolute, resolving any symlinks. A new path object is returned.

回答5:

The documentation says to use os.path.join():

The result may be either an absolute or relative pathname; if it is relative, it may be converted to an absolute pathname using os.path.join(os.path.dirname(path), result).