Running sha1sum into several directories

Question

I have several directories that share a common parent directory. In each directory there are regular files, but no other subdirectories. Something like this:

top/dir-1
top/dir-1/file-11
top/dir-1/file-12
top/dir-2
top/dir-2/file-21
top/dir-2/file-22
top/dir-3
top/dir-3/file-31
top/dir-3/file-32

I'd like to run sha1sum on those files and obtain the following checksum files:

top/dir-1/sha1sum
top/dir-2/sha1sum
top/dir-3/sha1sum

top/dir-1/sha1sum, for example, should contain only the checksums for file-11 and file-12:

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx file-11
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy file-12

I have tried several commands involving find, sha1sum, cd, a for loop and subshells, but without much success.

Last thing: both directories and files can have spaces in their names, so any solution should consider this.

Any ideas?

---

Edit. I finally tried with:

cd top
for i in *; do cd "${i}"; (sha1sum * > sha1sum); cd ..; done

It seems to work, but I'm still not sure if it's the right way for doing this kind of job.

Answer 1

Better as:

cd top &&
for i in */; do (cd -- "$i" && sha1sum -- * > sha1sum); done

Answer 2

A more generic approach (assuming you're already in top):

find . -type f -execdir bash -c 'for f; do sha1sum "${f##*/}" >> sha1sum; done' bash {} +

This should work regardless of your subdir structure and always output the checksum file in the same directory with the checked file(s).