Sorting the output of "find"?

Use find as usual and delimit your lines with NUL. GNU sort can handle these with the -z switch:

find . -print0 | sort -z | xargs -r0 yourcommand

Some versions of sort have a -z option, which allows for null-terminated records.

find folder1 folder2 -name "*.txt" -print0 | sort -z | xargs -r0 myCommand

Additionally, you could also write a high-level script to do it:

find folder1 folder2 -name "*.txt" -print0 | python -c 'import sys; sys.stdout.write("\0".join(sorted(sys.stdin.read().split("\0"))))' | xargs -r0 myCommand

Add the -r option to xargs to make sure that myCommand is called with an argument.

I think you need the -n flag for sort#

According to man sort:

-n, --numeric-sort
    compare according to string numerical value

edit

The print0 may have something to do with this, I just tested this. Take the print0 out, you can null terminate the string in sort using the -z flag