find exec 末尾的反斜杠和分号

$ find . -maxdepth 1 -type d -exec ls -ld "{}" \;

drwxr-xr-x 1 rui 197121 0 Feb 18 21:05 .
drwxr-xr-x 1 rui 197121 0 Feb 17 18:01 ./a
drwxr-xr-x 1 rui 197121 0 Dec 27 14:21 ./b
drwxr-xr-x 1 rui 197121 0 Feb  9 12:14 ./c
drwxr-xr-x 1 rui 197121 0 Feb 15 16:03 ./d

 

$ find . -maxdepth 1 -type d -exec ls -ld "{}"
find: missing argument to `-exec'