List all directories that contain >= 2 files/directories

list-more-than-2-files.sh

#!/bin/sh
# dependencies: find, grep, sort, uniq, awk

echo 'List all files...'
find $1
# output:
#   a
#   a/b
#   a/b/c
#   a/b/c/d
#   a/b/c/d/e
#   a/b/c/e
#   a/p
#   a/p/q
#   a/p/q/r
#   a/p/q/r/s
#   a/p/q/r/s/t
#   a/p/q/u

echo 'List all directories that contain >= 2 files/directories...'
find $1 | grep -o '.*/' | sort | uniq -d
# output:
#   a/
#   a/b/c/
#   a/p/q/