Explaining xargs output from two find commands

Question

I have a directory structure of

• folder1
  • folder2
    • folder2a
    • folder2b
  • folder3
    • folder3a
    • folder3b

I am confused by the xargs output of the below command:

XXXXXX:folder1 user$ find . -type d -maxdepth 1 | xargs -I{} find {} -type d -maxdepth 1 | xargs -I{} echo {}

.
./folder2
./folder3
./folder2
./folder2/folder2b
./folder2/folder2a
./folder3
./folder3/folder3a
./folder3/folder3b

I was expecting

./folder2
./folder2/folder2b
./folder2/folder2a
./folder3
./folder3/folder3a
./folder3/folder3b

Is the beginning output below from the first find command?

.
./folder2
./folder3

I thought the output of the first find command being piped as parameters to the second find and shouldn't be output. Where is the first part of the output coming from?

Answer 1

find . -type d -maxdepth 1 will have . in its output (the current directory), since it is a directory, and it has a depth less than 1. So you'll be running find on . again via xargs, which is how you get the extra output. You probably want -mindepth 1 as well for the first command:

$ find . -maxdepth 1 -mindepth 1 -type d | xargs -I{} find {} -type d -maxdepth 1 | xargs -I{} echo {}
./folder2
./folder2/folder2b
./folder2/folder2a
./folder3
./folder3/folder3a
./folder3/folder3b