Re: suspected 'ls' recursive listing when NOT requested bug in V6.4 GNU CoreUtils

[Eric Blake]

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According to andrew scott on 7/5/2007 8:39 AM:
> Dear GNU people,
> 
> Re: Core Utils V6.4 'ls' command

The latest stable version is 6.9; you may want to consider upgrading.

> 
> I am in my home directory.  I make a new sub-directory
> called 'p001_project'.  I have a file at the home
> level called 'p001_data.c'.  I use an ls command like
> this:-
> 
> ls -ls p001*

You used a glob, which is interpreted by the shell.  To see what you
actually did, you can use echo:

$ echo ls -ls p001*
ls -ls p001_data.c p001_project

Which lists the details of both p001_data.c and the p001_project directory
(which I'm guessing was empty at the time you tried this?).

> 
> and I get the file listed as expected.  I then move
> the file from home into the sub-directory and repeat
> the ls command:-
> 
> ls -ls p001*
> 
> and, amazingly, the file is still listed.  Note that I
> have NOT used the -R switch to ls, which would then
> make the command recursive.

Here, you did

ls -ls p001_project

and since you listed the directory which contains p001_data.c, it was
listed.  No recursion necessary.

> 
> If instead, I use this command:-
> 
> ls -ls p001_data.c
> 
> I get NO files listed.

Of course - because there is no p001_data.c in the current directory.

>  If I then issue this command:-
> 
> ls -lsR p001*
> 
> then I get a heading from ls saying there is a
> sub-directory present, in which the file is then
> listed as expected.

Yes, because now you issued the command:

ls -lsR p001_project

and p001_data.c happens to be encountered when recursively listing the
p001_project directory.

> 
> It seems to me me that somehow, if there is a wildcard
> present (the '*' in this example) then the command
> goes recursive on sub-directories without printing out
> the sub-directory heading.

No, actually what is happening is that the * is interpreted by the shell
prior to ls ever even seeing its command line arguments.  When handed a
directory, ls lists the directory contents when the -d flag is not in
effect.  For further proof, rename the directory to not start with the
same prefix as the file, and see what changes.  There is no bug in ls in
this regard.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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