Finds duplicates based on MD5 sum. Compares only files with the same size. Performance improvements on: find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate The new version takes around 3 seconds where the old version took around 17 minutes. The bottle neck in the old command was the second find. It searches for the files with the specified file size. The new version keeps the file path and size from the beginning.

* Find all file sizes and file names from the current directory down (replace "." with a target directory as needed). * sort the file sizes in numeric order * List only the duplicated file sizes * drop the file sizes so there are simply a list of files (retain order) * calculate md5sums on all of the files * replace the first instance of two spaces (md5sum output) with a \0 * drop the unique md5sums so only duplicate files remain listed * Use AWK to aggregate identical files on one line. * Remove the blank line from the beginning (This was done more efficiently by putting another "IF" into the AWK command, but then the whole line exceeded the 255 char limit). >>>> Each output line contains the md5sum and then all of the files that have that identical md5sum. All fields are \0 delimited. All records are \n delimited.

To allow recursivity : find -type f -exec md5sum '{}' ';' | sort | uniq -c -w 33 | sort -gr | head -n 5 | cut -c1-7,41- Display only filenames : find -maxdepth 1 -type f -exec md5sum '{}' ';' | sort | uniq -c -w 33 | sort -gr | head -n 5 | cut -c43- Show Sample Output