md5 all files in a directory tree

Question

I have a a directory with a structure like so:

.
├── Test.txt
├── Test1
│   ├── Test1.txt
│   ├── Test1_copy.txt
│   └── Test1a
│       ├── Test1a.txt
│       └── Test1a_copy.txt
└── Test2
   ├── Test2.txt
   ├── Test2_copy.txt
   └── Test2a
       ├── Test2a.txt
       └── Test2a_copy.txt

I would like to create a bash script that makes a md5 checksum of every file in this directory. I want to be able to type the script name in the CLI and then the path to the directory I want to hash and have it work. I'm sure there are many ways to accomplish this. Currently I have:

#!/bin/bash

for file in "$1" ; do 
    md5 >> "${1}__checksums.md5"
done

This just hangs and it not working. Perhaps I should use find?

One caveat - the directories I want to hash will have files with different extensions and may not always have this exact same tree structure. I want something that will work in these different situations, as well.

Ambidexter

Answer 1

Using md5deep

md5deep -r path/to/dir > sums.md5

Using find and md5sum

find relative/path/to/dir -type f -exec md5sum {} + > sums.md5

Be aware, that when you run check on your MD5 sums with md5sum -c sums.md5, you need to run it from the same directory from which you generated sums.md5 file. This is because find outputs paths that are relative to your current location, which are then put into sums.md5 file.

If this is a problem you can make relative/path/to/dir absolute (e.g. by puting $PWD/ in front of your path). This way you can run check on sums.md5 from any location. Disadvantage is, that now sums.md5 contains absolute paths, which makes it bigger.

Fully featured function using find and md5sum

You can put this function to your .bashrc file (located in your $HOME directory):

function md5sums {
  if [ "$#" -lt 1 ]; then
    echo -e "At least one parameter is expected\n" \
            "Usage: md5sums [OPTIONS] dir"
  else
    local OUTPUT="checksums.md5"
    local CHECK=false
    local MD5SUM_OPTIONS=""

    while [[ $# > 1 ]]; do
      local key="$1"
      case $key in
        -c|--check)
          CHECK=true
          ;;
        -o|--output)
          OUTPUT=$2
          shift
          ;;
        *)
          MD5SUM_OPTIONS="$MD5SUM_OPTIONS $1"
          ;;
      esac
      shift
    done
    local DIR=$1 

    if [ -d "$DIR" ]; then  # if $DIR directory exists
      cd $DIR  # change to $DIR directory
      if [ "$CHECK" = true ]; then  # if -c or --check option specified
        md5sum --check $MD5SUM_OPTIONS $OUTPUT  # check MD5 sums in $OUTPUT file
      else                          # else
        find . -type f ! -name "$OUTPUT" -exec md5sum $MD5SUM_OPTIONS {} + > $OUTPUT  # Calculate MD5 sums for files in current directory and subdirectories excluding $OUTPUT file and save result in $OUTPUT file
      fi
      cd - > /dev/null  # change to previous directory
    else
      cd $DIR  # if $DIR doesn't exists, change to it to generate localized error message
    fi
  fi
}

After you run source ~/.bashrc, you can use md5sums like normal command:

md5sums path/to/dir

will generate checksums.md5 file in path/to/dir directory, containing MD5 sums of all files in this directory and subdirectories. Use:

md5sums -c path/to/dir

to check sums from path/to/dir/checksums.md5 file.

Note that path/to/dir can be relative or absolute, md5sums will work fine either way. Resulting checksums.md5 file always contains paths relative to path/to/dir. You can use different file name then default checksums.md5 by supplying -o or --output option. All options, other then -c, --check, -o and --output are passed to md5sum.

First half of md5sums function definition is responsible for parsing options. See this answer for more information about it. Second half contains explanatory comments.

Cowpea

Note: In my experience using -exec command {} + variant of exec makes it run faster than when variant -exec command ; is used. – Cowpea

Thank you! I really appreciate having that complex (for me!) script commented out. – Ambidexter

Answer 2

How about:

find /path/you/need -type f -exec md5sum {} \; > checksums.md5

Update#1: Improved the command based on @twalberg's recommendation to handle white spaces in file names.

Update#2: Improved based on @jil's suggestion, to remove unnecessary xargs call and use -exec option of find instead.

Update#3: @Blake a naive implementation of your script would look something like this:

#!/bin/bash
# Usage: checksumchecker.sh <path>
find "$1" -type f -exec md5sum {} \; > "$1"__checksums.md5

Dulcia

I would recommend find /path -type f -print0 | xargs -0 md5sum, to deal with file names that otherwise might get unintentionally split due to whitespace... – Triiodomethane

Thank you @taskalman. "You can build the path and output file name from $1 if we put it in your script. Note that you will have to handle the slashes in your path parameter to make it part of the filename in your script." Can you explain this a bit further? I don't quite understand what you mean. – Ambidexter

@Blake sorry, misunderstood the logic, you van ignore that part, I remove it from the answer. I didn't realize you want tó save the file __checksums.md5 in the root of your search path. – Dulcia

@Dulcia I still want to use the $1 so that I don't haveto have to type out a find command each time, rather just a script name, say "makechecksum", and drop the directory to be hashed into the CLI. – Ambidexter

@Blake I added a naive script implementation. – Dulcia

@jil I like the globstar solution, it is pretty elegant. :) However, what will you do with the directories included? – Dulcia

@Dulcia Thanks! I think this works, but why do you call it naive? – Ambidexter

@Blake For instance, you may want to add a verification of the path's validity that you provide, print some data on the progress of the processing, etc. – Dulcia

Answer 3

Updated Answer

If you like the answer below, or any of the others, you can make a function that does the command for you. So, to test it, type the following into Terminal to declare a function:

function sumthem(){ find "$1" -type f -print0 | parallel -0 -X md5 > checksums.md5; }

Then you can just use:

sumthem /Users/somebody/somewhere

If that works how you like, you can add that line to the end of your "bash profile" and the function will be declared and available whenever you are logged in. Your "bash profile" is probably in $HOME/.profile

Original Answer

Why not get all your CPU cores working in parallel for you?

find . -type f -print0 | parallel -0 -X md5sum

This finds all the files (-type f) in the current directory (.) and prints them with a null byte at the end. These are then passed passed into GNU Parallel, which is told that the filenames end with a null byte (-0) and that it should do as many files as possible at a time (-X) to save creating a new process for each file and it should md5sum the files.

This approach will pay the largest bonus, in terms off speed, with big images like Photoshop files.

Runesmith

Yes, this would work, but I would have to continually re-type the whole command. I want a script where the directory to be hashed is a variable and the name of the file output is based on that variable. I don't want to have to type out a find command each time - just a script name, say "makechecksum", and drop the directory to be hashed into the CLI. – Ambidexter

Thanks! very helpful. – Ambidexter

I thought this would help, but in my case the (hard) disk was the bottleneck, because even with a single-thread the disk was maxed out. Just a thought. – Income

Answer 4

#!/bin/bash
shopt -s globstar
md5sum "$1"/** > "${1}__checksums.md5"

Explanation: shopt -s globstar(manual) enables ** recursive glob wildcard. It will mean that "$1"/** will expand to list of all the files recursively under the directory given as parameter $1. Then the script simply calls md5sum with this file list as parameter and > "${1}__checksums.md5" redirects the output to the file.

Inverness

@Blake Be aware that this won't hash hidden files. If you want hidden files to not be ignored, then activate dotglob option: shopt -s dotglob [source]. – Cowpea

@Inverness this is just hanging for me #!/usr/bin/env bash shopt -s globstar for file in "$1"/** ; do md5deep -br >> "${1}__checksums.md5" done – Ambidexter

Answer 5

md5deep -r $your_directory | awk {'print $1'} | sort | md5sum | awk {'print $1'}

Ashlieashlin

Please edit your answer to include some explanation. Code-only answers do very little to educate future SO readers. Your answer is in the moderation queue for being low-quality. – Householder

@AlexJurado-Bitendian did you check the answer, md5deep is not working in ubuntu 16.04 – Pliocene

Answer 6

Use find command to list all files in directory tree, then use xargs to provide input to md5sum command

find dirname -type f | xargs md5sum > checksums.md5

Schlimazel

Answer 7

In case you prefer to have separate checksum files in every directory, rather than a single file, you can

• find all subdirectories
• keep only those which actually contain files (not only other subdirs)
• cd to each of them and create a checksums.md5 file inside that directory

Here is a an example script which does that:

#!/bin/bash

# Do separate md5 files in each subdirectory

md5_filename=checksums.md5

dir="$1"
[ -z "$dir" ] && dir="."

# Check OS to select md5 command
if [[ "$OSTYPE" == "linux-gnu"* ]]; then
    is_linux=1
    md5cmd="md5sum"
elif [[ "$OSTYPE" == "darwin"* ]]; then
    md5cmd="md5 -r"
else
    echo "Error: unknown OS '$OSTYPE'. Don't know correct md5 command."
    exit 1
fi

# go to base directory after saving where we started
start_dir="$PWD"
cd "$dir"

# if we're in a symlink cd to the real path
if [ ! "$dir" = "$(pwd -P)" ]; then
    dir="$(pwd -P)"
    cd "$dir"
fi

if [ "$PWD" = "/" ]; then
    die "Refusing to do it on system root '$PWD'"
fi


# Find all folders to process

declare -a subdirs=()
declare -a wanted=()

# find all non-hidden subdirectories (not if the name begins with "." like ".Trashes", ".Spotlight-V100", etc.)
while IFS= read -r; do subdirs+=("$PWD/$REPLY"); done < <(find . -type d -not -name ".*" | LC_ALL=C sort)

# count files and if there are any, add dir to "wanted" array
echo "Counting files and sizes to process ..."
for d in "$dir" "${subdirs[@]}"; do  # include "$dir" itself, not only it's subdirs
    files_here=0
    while IFS= read -r ; do
        (( files_here  += 1 ))
    done < <(find "$d" -maxdepth 1 -type f -not -name "*.md5")

    (( files_here )) && wanted+=("$d")
done

echo "Found ${#wanted[@]} folders to process:"
printf "  * %s\n" "${wanted[@]}"

if [ "${#wanted[*]}" = 0 ]; then
    echo "Nothing to do. Exiting."
    exit 0
fi

for d in "${wanted[@]}"; do
    cd "$d"
    find . -maxdepth 1 -type f -not -name "$md5_filename" -print0 \
    | LC_ALL=C sort -z \
    | while IFS= read -rd '' f; do
            $md5cmd "$f" | tee -a "$md5_filename"
      done
    cd "$dir"
done

cd "$start_dir"

(This is actually a very simplified version of this "md5dirs" script on Github. The original is quite specific and more complex, making it less illustrative as an example, and more difficult to adapt to other different needs.)

Stellate

Answer 8

I wanted something similar to calculate the SHA256 of an entire directory, so I wrote this "checksum" script:

#!/bin/sh
cd $1
find . -type f | LC_ALL=C sort |
(
while read name; do
    sha256sum "$name"
done;
) | sha256sum

Example usage:

patrick@pop-os:~$ checksum tmp
d36bebfa415da8e08cbfae8d9e74f6606e86d9af9505c1993f5b949e2befeef0  -

In an earlier version I was feeding the file names to "xargs", but that wasn't working when file names had spaces.

Tyra