If path is symlink to another path

问题:

Is there a way in Python to check whether or not a file is a symlink to another specific file? For example, if /home/user/x symlinks to /home/user/z, but /home/user/y links somewhere else:

>>>print(isLink("/home/user/x", "/home/user/z")) True >>>print(isLink("/home/user/y", "/home/user/z")) False >>>print(isLink("/home/user/z", "/home/user/z")) False 

(/home/user/z is the original file, not a symlink)

回答1:

import os def isLink(a, b):     return os.path.islink(a) and os.path.realpath(a) == os.path.realpath(b) 

Note that this resolves the second argument to a real path. So it will return True if a and b are both symlinks, as long as they both point to the same real path. If you don't want b to be resolved to a real path, then change

os.path.realpath(a) == os.path.realpath(b) 

to

os.path.realpath(a) == os.path.abspath(b) 

Now if a points to b, and b points to c, and you want isLink(a, b) to still be True, then you'll want to use os.readlink(a) instead of os.path.realpath(a):

def isLink(a, b):     return os.path.islink(a) and os.path.abspath(os.readlink(a)) == os.path.abspath(b) 

os.readlink(a) evaluates to b, the next link that a points to, whereas os.path.realpath(a) evaluates to c, the final path that a points to.

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For example,

In [129]: !touch z  In [130]: !ln -s z x  In [131]: !touch w  In [132]: !ln -s w y  In [138]: isLink('x', 'z') Out[138]: True  In [139]: isLink('y', 'z') Out[139]: False  In [140]: isLink('z', 'z') Out[140]: False 

回答2:

This will do it.

os.path.realpath(path) 

Here are the docs.

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