In a large directory structure it is easy to inadvertently leave unnecessary copies of files around, which can use considerable disk space and create confusion.



Task

Create a program which, given a minimum size and a folder/directory, will find all files of at least size bytes with duplicate contents under the directory and output or show the sets of duplicate files in order of decreasing size.

The program may be command-line or graphical, and duplicate content may be determined by direct comparison or by calculating a hash of the data.

Specify which filesystems or operating systems your program works with if it has any filesystem- or OS-specific requirements.

Identify hard links (filenames referencing the same content) in the output if applicable for the filesystem.

For extra points, detect when whole directory sub-trees are identical, or optionally remove or link identical files.




from __future__ import print_function
import os
import hashlib
import datetime
 
def FindDuplicateFiles(pth, minSize = 0, hashName = "md5"):
    knownFiles = {}
 
    #Analyse files
    for root, dirs, files in os.walk(pth):
        for fina in files:
            fullFina = os.path.join(root, fina)
            isSymLink = os.path.islink(fullFina)
            if isSymLink:
                continue # Skip symlinks
            si = os.path.getsize(fullFina)
            if si < minSize:
                continue
            if si not in knownFiles:
                knownFiles[si] = {}
            h = hashlib.new(hashName)
            h.update(open(fullFina, "rb").read())
            hashed = h.digest()
            if hashed in knownFiles[si]:
                fileRec = knownFiles[si][hashed]
                fileRec.append(fullFina)
            else:
                knownFiles[si][hashed] = [fullFina]
 
    #Print result
    sizeList = list(knownFiles.keys())
    sizeList.sort(reverse=True)
    for si in sizeList:
        filesAtThisSize = knownFiles[si]
        for hashVal in filesAtThisSize:
            if len(filesAtThisSize[hashVal]) < 2:
                continue
            fullFinaLi = filesAtThisSize[hashVal]
            print ("=======Duplicate=======")
            for fullFina in fullFinaLi:
                st = os.stat(fullFina)
                isHardLink = st.st_nlink > 1 
                infoStr = []
                if isHardLink:
                    infoStr.append("(Hard linked)")
                fmtModTime = datetime.datetime.utcfromtimestamp(st.st_mtime).strftime('%Y-%m-%dT%H:%M:%SZ')
                print (fmtModTime, si, os.path.relpath(fullFina, pth), " ".join(infoStr))
 
if __name__=="__main__":
 
    FindDuplicateFiles('/home/tim/Dropbox', 1024*1024)
 