add

touch mkdir cp

del

rm rmdir

modify

touch vim echo

list

ls

find

find ${where} -${filter} -${exec}

# filter
type
[cma]time
empty
...

# exec
exec cmd -args "{}"  # {} == found.path

# e.g.
find . -empty -type d |while read line
do
    ls -l "$line/xxx"
done