How do I get rid of double duplicates files stored in ~/foo and /u2/foo directory?
You need to use a tool called fdupes. It will searche the given path for duplicate files. Such files are found by comparing file sizes and MD5 signatures, followed by a byte-by-byte comparison. fdupes is a nice tool to get rid of duplicate filesز
Type the following command under Debian / Ubuntu Linux:
# apt-get install fdupes
Type the following command under Redhat / RHEL / Fedota / CentOS Linux, enter (turn on rpmforge repo before running the following yum command):
# yum install fdupes
How Do I Use fdupes?
Find duplicate files in /etc/ directory, enter:
# fdupes /etc
How Do I Delete Unwanted Files?You can force fdupes to prompt you for files to preserve, deleting all others (use this with care otherwise you may loss data):
# fdupes -d /etc
 /etc/vimrc  /etc/virc Set 1 of 1, preserve files [1 - 2, all]: 1 [+] /etc/vimrc [-] /etc/virc
How Do Recursively Search Directory?You can recursively search every directory given follow subdirectories encountered within the -r option, enter:
# fdupes -r /dir1
How Do I Find Dupes In Two Directories?
Type the command as follows:
# fdupes /dir1 /dir2
# fdupes -r /etc /data/etc /nas95/etc
How Do I See Size Of Duplicate Files?
Type the following command with the -S option:
# fdupes -S /etc
1533 bytes each: /etc/vimrc /etc/virc
- man page fdupes