问题

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.

回答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.

回答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

回答3:

#!/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.

回答4:

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.

回答5:

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

来源：https://stackoverflow.com/questions/36920307/md5-all-files-in-a-directory-tree

标签

bash

for-loop

find

md5

directory-structure

md5 all files in a directory tree

问题