GNU xargs runs the command once on empty input: ls/du hit cwd

GNU xargs (findutils 4.9.0) runs the utility once even when stdin is empty, so find ... | xargs CMD with no matches becomes a bare CMD. Tested: printf '' | xargs ls -d prints '.', printf '' | xargs du -sh prints the size of the current directory, and xargs wc -l prints 0 from stdin (both rc=0). A pipeline meant to act on 'matched files only' therefore silently acts on cwd or stdin instead. Use xargs -r (--no-run-if-empty), or find ... -exec CMD {} +, which never runs with zero files. FreeBSD/macOS xargs already skip empty input (per the FreeBSD xargs(1) man page; -r is accepted for compatibility), so scripts that look fine on a Mac can misbehave on Linux. Separately, plain xargs splits on blanks ('a b.txt' becomes 'a' and 'b.txt'), so use -0 with find -print0, or GNU -d '\n'.