copy files with md5-based target name using find and xargs

Question

I have a directory tree with many .dat files, where many of them contain special characters. They are used by another process which is only able to process files containing ascii characters.

My idea was to find all the files, build a new file name based on the md5 hash of their file path, and copy them to a new directory (they aren't very large, and I may not alter the originals).

This is what I've tried

find dat -type f -name "*.dat" -print0|xargs -0 -I file cp 'file' "datnew/$(echo file|md5).dat"

Unfortuntately it only builds a single hash, and copy all files to that output file name:

$ touch dat/foo.dat
$ touch dat/bar.dat
$ find dat -type f -name "*.dat" -print0|xargs -0 -I file cp 'file' "datnew/$(echo file|md5).dat"
$ ls datnew
bbe02f946d5455d74616fc9777557c22.dat

Can you please tell me what my mistakte is? Am I using xargsin a wrong way?

Answer 1

As file in $( echo $file | md5 ) will not be interpreted, you need a workaround.

One possibility is to simply pipe it into a while loop and read each output - in that case better skip xargs as a whole

find ... | while read file ; do cp "$file" "datnew/$( echo "$file" | md5 )" ; done

For using it with -print0 replace the null character with a newline using tr

find ... -print0 | tr '\000\' '\n' | while read ; do ... ; done