One of the easiest and safest ways to find duplicate files on GNU / Linux files is using the tool fdupes, fdupes find duplicate files comparing the file sizes, making a check MD5 followed by a byte to byte comparison.
You can install fdupes using following command:
Debian GNU/Linux
$ sudo apt-get install fdupes
CentOS/Fedora/RHEL/BLAG is necessary to use RPMForge
# yum -y install fdupes
Synopsis
fdupes [opciones] path
Some options:
-r: Performs a recursive search for all dir in path
-R: Performs a recursive lookup for directories given after the choice
-s: Follows symbolic links
-n: Does not check empty files
Examples:
Recursive in b but not in a.
$ fdupes a -R b
Recursive search in a and b.
$ fdupes a -r b
Further reading
– man fdupes