rsync -rc original-dir/ copied-dir/
-c causes rsync to compare files by MD5 checksum (without it, it normally uses only the timestamp and size for quicker comparisons).
This will also cause rsync to copy whatever it sees different or missing from the destination. To avoid that, you can also use
-i. The former ensures that rsync doesn't do any change and only compares, and the latter causes it to display the differences that it sees.
For example, I have the following dirs:
$ find dir1/ dir2/
$ rsync -rcni dir1/ dir2/
Tells me, by way of all those
+s, that file
c does not exist in
dir2, and file
d/b does, but is different (indicated by the
c in the first column). The
T says that it's time would be updated (had we not used
The format of
-i's output is described in the manpage for rsync. You can
man rsync and get to the part that explains that output by typing
/--itemize-changes$ (and hitting Enter).