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I'd like to find an md5sum (or similar calculation) of a folder without compressing it into an archive.

For example, if in the folder MyFolder we have the files 1.txt, 2.txt and 3.txt, containing:


The text into 1.txt


The text into 2.txt


The text into 3.txt

How can I calculate the md5sum of this entire MyFolder? Is there a way? I want to use this to verify if two folders have the same contents.

This can be util to verify if two cds or folders are equal. I'd like a easy way to do it.

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3 Answers 3

up vote 12 down vote accepted

The md5deep tool was developed for precisely this purpose. Many Linux distributions offer it in package form.

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Thx! It's worked fine to me. To other users with the same problem to like this: sudo apt-get install md5deep md5deep -rel /path/to/your/directory/ > directory_hash.md5 md5deep -X directory_hash.md5 -r /path/to/your/second/direcotory Thx a lot. –  GarouDan Oct 17 '11 at 1:15
@GarouDan. The command you have shown will follow symbolic links. You can use the -o option to handle file types. –  Peter.O Oct 17 '11 at 7:16
Oh thx...don't know that...really helpfull. I'll remember! –  GarouDan Oct 18 '11 at 10:00

If you don't want to archive it, maybe you could do something like this

diff <(find folder1) <(find folder2)

You may have to adapt the find commands to be more accurate.

EDIT You could add -exec to your find call to compare the content of files. Something similar to this:

diff <(find folder1 -type f -exec md5sum {} \; | sort) <(find folder2 -type f -exec md5sum {} \; | sort)

Remember that you may want to adapt this.

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It's an interesting point. This lists all files of each folder...but if I have a really great amount of archives... how could verify there are the same files (with the data - maybe using a md5sum tool) in each folder? –  GarouDan Oct 16 '11 at 23:49
Then do a diff of the MD5SUM output of each file. You just need to string together the find, md5sum and diff commands differently. –  sybreon Oct 17 '11 at 0:01
Thx about your ideas too, cya...I will try interesting things with these find comand after...thanks. –  GarouDan Oct 17 '11 at 1:16

One way to test could be to generate an md5sum based on the concatenation of all of the files in the folder and its subfolders. Bear in mind that this also requires that the files have the same names (as they must be in the same sort order). The following code should work:


shopt -s nullglob
shopt -s globstar || { printf '%s\n' 'Bash 4 is required for globstar.' ; exit 1 ; }
(( $# == 2 )) || { printf '%s\n' "Usage: ${0##*/} olddir newdir" ; exit 2 ; }

for _file in "$1"/**/*; do [[ -f ${_file} && ! -L ${_file} ]] && _files_in_old_dir+=( "${_file}" ); done
for _file in "$2"/**/*; do [[ -f ${_file} && ! -L ${_file} ]] && _files_in_new_dir+=( "${_file}" ); done

(( ${#_files_in_old_dir[@]} )) || { printf '%s\n' 'No files in old dir.' ; exit 3 ; }
(( ${#_files_in_new_dir[@]} )) || { printf '%s\n' 'No files in new dir.' ; exit 4 ; }

_md5_old_dir=$(cat "${_files_in_old_dir[@]}" | md5sum)
_md5_new_dir=$(cat "${_files_in_new_dir[@]}" | md5sum)

{ [[ ${_md5_old_dir} == "${_md5_new_dir}" ]] && (( ${#_files_in_old_dir[@]} == ${#_files_in_new_dir[@]} )) ; } && printf '%s\n' 'Folders are identical.' || { printf '%s\n' 'Folders are not identical.' ; exit 3 ; }

If you truly care about the file names, etc, you could use a loop to compare what is in ${_files_in_old_dir} and ${_files_in_new_dir}. This should work for most cases (it at least checks the number of files in the dir and its subdirectories).

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This is a nice script...thx @Chris . But it have a problem...using cat, subfolders crashes with errors... Do you have a idea to solve it? Thx a lot. –  GarouDan Oct 17 '11 at 1:29
It works fine for me. Make sure your shell supports globstar. What is the error? –  Chris Down Oct 17 '11 at 1:59
It "works" (+1)... but globstar in bash 4 follows directory symlinks, but that's only a problem if either directory contains a symlink. –  Peter.O Oct 17 '11 at 7:14
@fered Good call, I added in a test. –  Chris Down Oct 17 '11 at 11:04

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