Strange kind of "stealth" directory on Linux

Question

I am in a Linux machine and am working with a directory that is aptly named "stealth", because it runs and hides! Take a look at this behavior:

bash-3.2$ ls /net
bash-3.2$ ls -la /net
total 4
drwxr-xr-x  2 root root    0 Jun 19 16:10 .
drwxr-xr-x 29 root root 4096 Jun 15 09:51 ..
bash-3.2$ ls /net/stealth
dir1  dir2  SERVER_LINK
bash-3.2$ ls /net
stealth
bash-3.2$ ls -la /net
total 4
drwxr-xr-x  3 root root    0 Jun 19 16:59 .
drwxr-xr-x 29 root root 4096 Jun 15 09:51 ..
dr-xr-xr-x  6 root root    0 Jun 19 16:59 stealth
bash-3.2$ uname -a
Linux cfnyps1u 2.6.18-348.18.1.el5 #1 SMP Fri Sep 6 12:37:18 EDT 2013 x86_64 x86_64 x86_64 GNU/Linux

(Note the difference between the output of ls /net before and after the contents of the stealth directory are listed)

What is the name of this type of directory, and why would it "hide" until it is "found"? I eventually figured out what was going on, but I'd never seen this behavior before and it definitely makes the directory's contents harder to find using standard approaches.

Answer 1

You are seeing autofs behaviour. /net tends to contain directories that are auto-mounted. Auto-mounted directories aren't mounted until you specifically use them. They will stay mounted for a set amount of time, and then if not used in that time period, they are automatically unmounted.

Try running

man autofs

to see documentation about this.