Given two directory trees, how can I find out which files differ by content?

Question

If I want find the differences between two directory trees, I usually just execute:

diff -r dir1/ dir2/

This outputs exactly what the differences are between corresponding files. I'm interested in just getting a list of corresponding files whose content differs. I assumed that this would simply be a matter of passing a command line option to diff, but I couldn't find anything on the man page.

Any suggestions?

Answer 1

Try:

diff --brief --recursive dir1/ dir2/

Or alternatively, with the short flags -qr:

diff -qr dir1/ dir2/

If you also want to see differences for files that may not exist in either directory:

diff --brief --recursive --new-file dir1/ dir2/  # with long options
diff -qrN dir1/ dir2/                            # with short flag aliases

Answer 2

The command I use is:

diff -qr dir1/ dir2/

It is exactly the same as Mark's :) But his answer bothered me as it uses different types of flags, and it made me look twice. Using Mark's more verbose flags it would be:

diff  --brief --recursive dir1/ dir2/

_{I apologise for posting when the other answer is perfectly acceptable. Could not stop myself... working on being less pedantic.}

Answer 3

I like to use git diff --no-index dir1/ dir2/, because it can show the differences in color (if you have that option set in your git config) and because it shows all of the differences in a long paged output using "less".

Answer 4

Using rsync:

rsync --dry-run --recursive --delete --links --checksum --verbose /dir1/ /dir2/ > dirdiff_2.txt
# or same in short
rsync -nrlcv --delete /dir{1,2}/ > dirdiff_2.txt

Alternatively, using diff:

diff --brief --recursive --no-dereference --new-file --no-ignore-file-name-case /dir1 /dir2 > dirdiff_1.txt
# or same in short
diff -qrN --no-dereference --no-ignore-file-name-case /dir{1,2} > dirdiff_1.txt

They are functionally equivalent, but performance may vary depending on:

• If the directories are on the same drive, rsync is faster.
• If the directories reside on two separate drives, diff is faster.

This is because diff puts an almost equal load on both directories in parallel, maximizing load on the two drives. rsync calculates checksums in large chunks before actually comparing them. That groups the i/o operations in large chunks and leads to a more efficient processing when things take place on a single drive.

Answer 5

Meld is also a great tool for comparing two directories:

meld dir1/ dir2/

Meld has many options for comparing files or directories. If two files differ, it's easy to enter file comparison mode and see the exact differences.

Answer 6

Channel compatriot 'billings' (of freenode/#centos fame) shared his method with me:

diff -Naur dir1/ dir2

Including the final directory forward slash doesn't matter.

Also, it appears the -u option is not available on some older/server versions of diff.

The difference in diffs:

# diff -Nar /tmp/dir1 /tmp/dir2/
diff -Nar /tmp/dir1/file /tmp/dir2/file
28a29
> TEST

# diff -qr /tmp/dir1/ /tmp/dir2/
Files /tmp/dir1/file and /tmp/dir2/file differ

Answer 7

To find diff use this command:

diff -qr dir1/ dir2/

-r will diff all subdirectories too -q tells diff to report only when files differ.

diff  --brief dir1/ dir2/

--brief will show the files that dosent exist in directory.

Or else

we can use Meld which will show in graphical window its easy to find the difference.

meld  dir1/ dir2/

Answer 8

Diffoscope is a great command line based directory diff tool.

I especially like about it that it can diff into files:

It will recursively unpack archives of many kinds and transform various binary formats into more human readable form to compare them. It can compare two tarballs, ISO images, or PDF just as easily.

It will not only tell you which files differ, but also how they differ.

Answer 9

You can also use Rsync and find. For find:

find $FOLDER -type f | cut -d/ -f2- | sort > /tmp/file_list_$FOLDER

But files with the same names and in the same subfolders, but with different content, will not be shown in the lists.

If you are a fan of GUI, you may check Meld that @Alexander mentioned. It works fine in both windows and linux.

Answer 10

To report differences between dirA and dirB, while also updating/syncing:

rsync -auv <dirA> <dirB>