Comparing the contents of two directories

You can use the diff command just as you would use it for files:

diff <directory1> <directory2>

If you want to see subfolders and -files too, you can use the -r option:

diff -r <directory1> <directory2>

A good way to do this comparison is to use find with md5sum, then a diff.

Example

Use find to list all the files in the directory then calculate the md5 hash for each file and pipe it sorted by filename to a file:

find /dir1/ -type f -exec md5sum {} + | sort -k 2 > dir1.txt

Do the same procedure to the another directory:

find /dir2/ -type f -exec md5sum {} + | sort -k 2 > dir2.txt

Then compare the result two files with diff:

diff -u dir1.txt dir2.txt

Or as a single command using process substitution:

diff <(find /dir1/ -type f -exec md5sum {} + | sort -k 2) <(find /dir2/ -type f -exec md5sum {} + | sort -k 2)

If you want to see only the changes:

diff <(find /dir1/ -type f -exec md5sum {} + | sort -k 2 | cut -f1 -d" ") <(find /dir2/ -type f -exec md5sum {} + | sort -k 2 | cut -f1 -d" ")

The cut command prints only the hash (first field) to be compared by diff. Otherwise diff will print every line as the directory paths differ even when the hash is the same.

But you won't know which file changed...

For that, you can try something like

diff <(find /dir1/ -type f -exec md5sum {} + | sort -k 2 | sed 's/ .*\// /') <(find /dir2/ -type f -exec md5sum {} + | sort -k 2 | sed 's/ .*\// /')

This strategy is very useful when the two directories to be compared are not in the same machine and you need to make sure that the files are equal in both directories.

Another good way to do the job is using Git’s diff command (may cause problems when files has different permissions -> every file is listed in output then):

git diff --no-index dir1/ dir2/

Through you are not using bash, you can do it using diff with --brief and --recursive:

$ diff -rq dir1 dir2 
Only in dir2: file2
Only in dir1: file1

The man diff includes both options:

-q, --brief
report only when files differ

-r, --recursive
recursively compare any subdirectories found

Maybe one option is to run rsync two times:

rsync -rtOvcs --progress -n /dir1/ /dir2/

With the previous line, you will get files that are in dir1 and are different (or missing) in dir2.

rsync -rtOvcs --progress -n /dir2/ /dir1/

The same for dir2

#from the rsync --help :
-n, --dry-run               perform a trial run with no changes made

-r, --recursive             recurse into directories
-t, --times                 preserve modification times
-O, --omit-dir-times        omit directories from --times
-v, --verbose               increase verbosity
    --progress              show progress during transfer
-c, --checksum              skip based on checksum, not mod-time & size
-s, --protect-args          no space-splitting; only wildcard special-chars

You can delete the -n option to undergo the changes. That is copying the list of files to the second folder.

In case you do that, maybe a good option is to use -u, to avoid overwriting newer files.

-u, --update                skip files that are newer on the receiver

A one-liner:

rsync -rtOvcsu --progress -n  /dir1/ /dir2/ && rsync -rtOvcsu --progress -n /dir2/ /dir1/

Here is an alternative, to compare just filenames, and not their contents:

diff <(cd folder1 && find . | sort) <(cd folder2 && find . | sort)

This is an easy way to list missing files, but of course it won't detect files with the same name but different contents!

(Personally I use my own diffdirs script, but that is part of a larger library.)

I would like to suggest a great tool that I have just discover: MELD.

It works properly and everything you can do with the command diff on Linux-based system, can be there replicated with a nice Graphic Interface!

For instance, the comparison of directories is straightforward:

and also the files comparison is made easier:

There is a nice integration with some control version (for instance Git) and can be used as merge tool. See the complete documentation on its website.

If you want to make each file expandable and collapsible, you can pipe the output of diff -r into Vim.

First let's give Vim a folding rule:

mkdir -p ~/.vim/ftplugin
echo "set foldexpr=getline(v:lnum)=~'^diff.*'?'>1':1 foldmethod=expr fdc=2" >> ~/.vim/ftplugin/diff.vim

Now just:

diff -r dir1 dir2 | vim - -R

You can hit zo and zc to open and close folds. To get out of Vim, hit :q<Enter>

The -R is optional, but I find it useful alongside - because it stops Vim from bugging you to save the buffer when you quit.

Inspired by Sergiy's reply, I wrote my own Python script to compare two directories.

Unlike many other solutions it doesn't compare contents of the files. Also it doesn't go inside subdirectories which are missing in one of the directories. So the output is quite concise and the script works fast with large directories.

#!/usr/bin/env python3

import os, sys

def compare_dirs(d1: "old directory name", d2: "new directory name"):
    def print_local(a, msg):
        print('DIR ' if a[2] else 'FILE', a[1], msg)
    # ensure validity
    for d in [d1,d2]:
        if not os.path.isdir(d):
            raise ValueError("not a directory: " + d)
    # get relative path
    l1 = [(x,os.path.join(d1,x)) for x in os.listdir(d1)]
    l2 = [(x,os.path.join(d2,x)) for x in os.listdir(d2)]
    # determine type: directory or file?
    l1 = sorted([(x,y,os.path.isdir(y)) for x,y in l1])
    l2 = sorted([(x,y,os.path.isdir(y)) for x,y in l2])
    i1 = i2 = 0
    common_dirs = []
    while i1<len(l1) and i2<len(l2):
        if l1[i1][0] == l2[i2][0]:      # same name
            if l1[i1][2] == l2[i2][2]:  # same type
                if l1[i1][2]:           # remember this folder for recursion
                    common_dirs.append((l1[i1][1], l2[i2][1]))
            else:
                print_local(l1[i1],'type changed')
            i1 += 1
            i2 += 1
        elif l1[i1][0]<l2[i2][0]:
            print_local(l1[i1],'removed')
            i1 += 1
        elif l1[i1][0]>l2[i2][0]:
            print_local(l2[i2],'added')
            i2 += 1
    while i1<len(l1):
        print_local(l1[i1],'removed')
        i1 += 1
    while i2<len(l2):
        print_local(l2[i2],'added')
        i2 += 1
    # compare subfolders recursively
    for sd1,sd2 in common_dirs:
        compare_dirs(sd1, sd2)

if __name__=="__main__":
    compare_dirs(sys.argv[1], sys.argv[2])

If you save it to a file named compare_dirs.py, you can run it with Python3.x:

python3 compare_dirs.py dir1 dir2

Sample output:

user@laptop:~$ python3 compare_dirs.py old/ new/
DIR  old/out/flavor-domino removed
DIR  new/out/flavor-maxim2 added
DIR  old/target/vendor/flavor-domino removed
DIR  new/target/vendor/flavor-maxim2 added
FILE old/tmp/.kconfig-flavor_domino removed
FILE new/tmp/.kconfig-flavor_maxim2 added
DIR  new/tools/tools/LiveSuit_For_Linux64 added

P.S. If you need to compare file sizes and file hashes for potential changes, I published an updated script here: https://gist.github.com/amakukha/f489cbde2afd32817f8e866cf4abe779

Fairly easy task to achieve in python:

python -c 'import os,sys;d1=os.listdir(sys.argv[1]);d2=os.listdir(sys.argv[2]);d1.sort();d2.sort();x="SAME" if d1 == d2 else "DIFF";print x' DIR1 DIR2

Substitute actual values for DIR1 and DIR2.

Here's sample run:

$ python -c 'import os,sys;d1=os.listdir(sys.argv[1]);d2=os.listdir(sys.argv[2]);d1.sort();d2.sort();x="SAME" if d1 == d2 else "DIFF";print x' Desktop/ Desktop
SAME
$ python -c 'import os,sys;d1=os.listdir(sys.argv[1]);d2=os.listdir(sys.argv[2]);d1.sort();d2.sort();x="SAME" if d1 == d2 else "DIFF";print x' Desktop/ Pictures/
DIFF

For readability, here's an actual script instead of one-liner:

#!/usr/bin/env python
import os, sys

d1 = os.listdir(sys.argv[1])
d2 = os.listdir(sys.argv[2])
d1.sort()
d2.sort()

if d1 == d2:
    print("SAME")
else:
    print("DIFF")

Adail Junior's nice answer might have an issue in time execution if you have hundreds of thousands of files! So here is another way to do it. Say you want to compare all the filenames of folder A with all the filenames of folder B. Step 1, cd to folder A and do:

find . | sort -k 2 > listA.txt

Step 2, cd to folder B and do:

find . | sort -k 2 > listB.txt

Step 3, take the diff of listA.txt and listB.txt

I tried that in folders containing half a million txt files and in less than 30 secs I had the diff on my screen, whereas computing the md5sums and then piping and then appending can be very very time consuming. Note also the original question is asking for comparing filenames (not their content!) and check if there are files missing between the folders under comparison! Thanks