chownR_If: For every file+dir rooted at `root`, if the owner of that file/dir is `targetUid`, then change the owner to `replacementUid`.

chownR_if.py

#! /usr/bin/env python3

import os

def chownIf(path, targetUid, replacementUid ):
    """If the owner of `path` is `targetUid`, then change the owner to `replacementUid`.
       (UID's are numeric, not string.)
       BUG -- this doesn't work: Also, if a link is owned by root(0), change it to `replacementUid` as well.
    """
    ownerUid = os.stat(path).st_uid 
    if ownerUid == targetUid:
        print( "Changing from owner " + str(ownerUid) + " to " + str(targetUid) + " for " + path 
        os.chown(path, replacementUid, -1, follow_symlinks=False)
    if os.path.islink(path) and ownerUid == 0:
        # bug: this doesn't seem to work (the unix `chown` doesn't change link owners ... but it rarely matters?)
        os.chown(path, replacementUid, -1, follow_symlinks=False)


def chownRIf( root, targetUid, replacementUid ):
    """For every file rooted at `root`, including `.`, `chownIf` it (see `chownIf`)."""
    chownIf(root,targetUid,replacementUid)  # `.` handled specially (!)
    for (subdir,dirs,files) in os.walk(root):
        for name in dirs+files:
            chownIf(os.path.join(subdir,name), targetUid, replacementUid)


chownRIf( "/Users/ibarland/Tmp/Tmp2", 501, 502 )