Parallel md5sum on all *.txt files in directory

Question

Trying to calculate md5 hash of all *.txt files in directory and store each in same filename but with extension replaced from .txt to .md5.

For file: foo.txt i want to create file: foo.md5 with content:

9fa74bee342222aadd999b2e8b2bef62 *foo.txt

I have managed to get needed files with command below, but I wonder is there some much shorter alternative, or at least a way to drop one or two awk commands?

time find *.txt | parallel md5sum | awk '{ print $1, $2, $2 }' | awk '{$1 $2 $3 > gsub(".txt", ".md5", $3); print}' | awk '{ print $1, "*"$2 > $3 }'

I have found some alternatives, but they don't use parallel and the just add .md5 to filename, not replace it. Also they store only md5 hash, I need this *filename modification.

Answer 1

Create a function and run with parallel:

_md5(){
  md5sum -b "$1" > "$1.md5"
}
export -f _md5

parallel -j8 _md5 ::: *.txt

Use "${1%.*}".md5 to replace the extension with md5 instead of appending it.

Answer 2

With zsh:

autoload zargs
m5() md5sum < $1 > $1:r.md5
zargs -l1 -rP8 -- **/*.txt(ND.) -- m5

Or with GNU utilities and any shell:

LC_ALL=C find . -name '*.txt' -type f -print0 |
  xargs -r0 -l1 -P8 sh -c 'exec md5sum < "$1" > "${1%.*}.md5"' sh