How to pipe a the output of find to another find invocation

Question

Here's what I'm trying to do

find . -maxdepth 1 -type d -print0 | xargs -0 -P4 find -name 'war' -type d

I would like to create a list of directory names, null-terminated, and then pass this list to xargs, which for each directory name calls find using a pool of 4 processes.

My problem is: How do I access stdin in the piped-to find command? Something like

find <STDIN> -name 'war' -type d

Answer 1

use this:

find . -maxdepth 1 -type d -print0 |
xargs -0 -I {} -P4 find "{}" -name "war" -type d

better way is exclude . path:

find . -maxdepth 1 -not -path .  -type d -print0 |
xargs -0 -I "{}"  find "{}" -name "war" -type d

Answer 2

Find cannot read its path from stdin, you cannot specify - like with many other programs.

I recommend that you use GNU parallel to run things in parallel:

find . -mindepth 1 -maxdepth 1 -type d -print0  | parallel -0 --jobs 4 \
    find {} -name "war" -type d

Please note the added -mindepth 1 to the first find. If you don't include that, the current directory (.) will be passed in to one of the finds as well and you will get double results.

$ mkdir a b c d e
$ mkdir b/war c/war
$ find . -mindepth 1 -maxdepth 1 -type d -print0  | parallel -0 --jobs 4 \
    find {} -name "war" -type d
./b/war
./c/war
$ find . -maxdepth 1 -type d -print0  | parallel -0 --jobs 4 \
    find {} -name "war" -type d
./c/war
./b/war
./c/war
./b/war