在 Linux 中使用 ls 仅显示目录

Question

I'm getting myself familiar with Linux (Debian 9). However I managed to get myself confused with the ls command manual. I made up the following trivial setting for testing:

 meouser:~/triv_dir$ ls -laR.: total 24 drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:42. drwxr-xr-x 19 meouser meouser 4096 Mar 27 15:41.. drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:55 a drwxr-xr-x 2 meouser meouser 4096 Mar 27 15:42 b -rw-r--r-- 1 meouser meouser 6 Mar 27 15:44 c -rw-r--r-- 1 meouser meouser 6 Mar 27 15:44 d./a: total 24 drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:55. drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:42.. -rw-r--r-- 1 meouser meouser 4 Mar 27 15:50 aa -rw-r--r-- 1 meouser meouser 4 Mar 27 15:50 ab drwxr-xr-x 2 meouser meouser 4096 Mar 27 15:55 a_sub_1 drwxr-xr-x 2 meouser meouser 4096 Mar 27 15:55 a_sub_2./a/a_sub_1: total 12 drwxr-xr-x 2 meouser meouser 4096 Mar 27 15:55. drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:55.. -rw-r--r-- 1 meouser meouser 4 Mar 27 15:55 aaa./a/a_sub_2: total 8 drwxr-xr-x 2 meouser meouser 4096 Mar 27 15:55. drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:55.../b: total 16 drwxr-xr-x 2 meouser meouser 4096 Mar 27 15:42. drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:42.. -rw-r--r-- 1 meouser meouser 4 Mar 27 15:50 ba -rw-r--r-- 1 meouser meouser 4 Mar 27 15:50 bb

I would like to see all the directory names and their subdirectories, but not the filenames. That is, I want something like ls --insert-options-here so that the output is this subset from above:

 .: total 24 drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:42. drwxr-xr-x 19 meouser meouser 4096 Mar 27 15:41.. drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:55 a drwxr-xr-x 2 meouser meouser 4096 Mar 27 15:42 b./a: total 24 drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:55. drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:42.. drwxr-xr-x 2 meouser meouser 4096 Mar 27 15:55 a_sub_1 drwxr-xr-x 2 meouser meouser 4096 Mar 27 15:55 a_sub_2

According to ls manual that should be achieved by ls -ldR .

 meouser:~/triv_dir$ man ls -a, --all do not ignore entries starting with. -d, --directory list directories themselves, not their contents -l use a long listing format -R, --recursive list subdirectories recursively

But this is what happens instead: only the '.' is shown.

 meouser:~/triv_dir$ ls -ldR drwxr-xr-x 4 meouser meouser 4096 Mar 27 15:42.

What am I missing from the manual?

I noticed from https://stackoverflow.com/a/29277454/11199684 that this can be achieved by find. -maxdepth 2 -type d -print find. -maxdepth 2 -type d -print which is impressive but it gives less information than the ls output above. Besides, I might not know beforehand the correct maxdepth? And above all, for future needs I'm actually interested in teaching myself from the manuals. Advice are appreciated.

Answer 1

The -d option apply to [FILE] given as input, in your case, as none are given, you fall back to the default one: the current directory. The recursivity doesn't apply as no directory are returned.

To get the same output as ls with the find command, you can combine them:

 find. -type d -exec ls -ld {} \;

Answer 2

in some way you could use the grep tool to filter the results:

 ll -A | grep ^d

if you want to use it programatically, in a bash script you can have only the dir names (but find might be better for that):

 ll -A | grep / | awk '{print $9}'