Dear all,

I may be asking a basic question, but I could not find a satisfactory explanation online.
I use an Ubuntu 18.04 Operating System and I was in search of a folder that I knew it should have been there, but it was not, or at least it did not appear in the list when I was typing the command "ls". Then I used the command "find" {folder_name} and the folder suddenly appeared there after typing "ls".

Could someone explain to me why this happened and if it is really related to the command "find"?

Thank you very much in advance!

quick answer:
a search on duckduckgo for: linux find command
leads me to this...

The currently active path marks the search location, by default. To search the entire drive, type the following:

find / filename

it is my understanding that a simple: ls command only lists the current directory

welcome to lq

1 members found this post helpful.

Hard to imagine how the find command could make a folder appear. Are you sure you were in the same current directory when you did the first "ls"?

Since you did not give the full command line for the "ls" command, all I can think you may have done is this.

This lists nothing, if the folder is empty.
This lists the folder, if it exists.
This lists the FOLDER_NAME too and any other files or folders under the folder, if there are any.
Just a thought.

1 members found this post helpful.

In both of the replies so far, the find command was issued without telling it what to look for. I didn't think that worked.

I think you need to tell it what you want with

for a case insensitive search starting at the root for files named filename or

for a search starting at the current working directory for directories named Icons.

Why? Recent versions of GNU find default to . as search root and to -print as action.

Is it possible, that the file is hidden and that is why you can't see it?

2 members found this post helpful.

By default, ls searches only the current directory (-R changes this). On the other hand, by default, find searches everything under the current directory. Therefore, if you have this structure:

/dir1/dir2/myfile

and you do 'ls' or 'ls myfile' from /dir1 (or from /), you will not find it. However, 'find myfile' will find it, but only show you the filename, not which directory it was found in. A more useful command in this situation would be 'ls -R|grep myfile'.

From your description, I'm not sure if this fits your problem, but maybe it'll help.

i think i might have misunderstood the question

are you trying to find out if this is normal behavior?
if your description of events is correct...
when you entered these commands in this order: ls, find foldername, ls
these were your results:

ls ---you did not see? the file listed
find foldername ---i am not sure what your result were?
ls ---for some strange reason the folder is now listed!

as long as you did not change directories, i would say this is not normal behaviour
am i on the right track? [i am far from an expert]

The only thinkable mechanism is an automount.
Check with df foldername if it's a separate (mounted) filesystem.
If yes:
The classic autofs always shows the folder. Only ls -l shows arbitrary attributes when not mounted.
I am not yet familiar with the x-systemd.automount - check for this option in /etc/fstab!
Another "late mount" mechanism might exist.

Try:

• Issue 'ls' as '\ls'. This will ignore any alias that's defined.
• If the above works, issue "alias | grep ls" and see if there's an unusual alias defined that's affecting the way 'ls' is working. (For example, using some odd switch like '--hide=...'.) If you find an alias defined for 'ls', do you really need it? If it's defined systemwide and you can't -- or do not wish to -- remove it, you can override with an alias of your own:
  
  Code:

  alias ls='\ls'                              # The plainest vanilla ls you can get
  alias ls='\ls <other switches you prefer>   # Plain vanilla but customized by you
  alias ls='_ls'                              # Vanilla but uses /etc/DIR_COLORS

  (I ran across that last one in some documentation ages ago. Don't ask where; I've forgotten the source.)
  
  You'd need to put one of those in a file and source it in your .profile or simply include it in the .profile directly.

HTH...