Command line example for symbolic link may cause problems

[Anonymous]

On this page: ​https://docs.djangoproject.com/en/1.4/topics/install/

The command line "ln -s WORKING-DIR/django-trunk/django/bin/django-admin.py /usr/local/bin"
is suggested. This creates a linked file named "bin" inside /usr/local/, instead of creating a link inside the directory /usr/local/bin/.

The suggested command line should be "ln -s WORKING-DIR/django-trunk/django/bin/django-admin.py /usr/local/bin/"
(slash on the end).

[Adrien Lemaire]

I don't see any problem with adding a slash to the doc.

But I don't understand either what problems this lack of slash may engender. Could you give me an example ? As far as I know, /usr/local/bin is a directory in any unix directory structure, and ln -s should work as expected, slash or not

[noria]

The top of the LN man page :

---

NAME

ln - make links between files

SYNOPSIS

ln [OPTION]... [-T] TARGET LINK_NAME (1st form)
ln [OPTION]... TARGET (2nd form)
ln [OPTION]... TARGET... DIRECTORY (3rd form)
ln [OPTION]... -t DIRECTORY TARGET... (4th form)

DESCRIPTION

In the 1st form, create a link to TARGET with the name LINK_NAME. In
the 2nd form, create a link to TARGET in the current directory. In the
3rd and 4th forms, create links to each TARGET in DIRECTORY. Create
hard links by default, symbolic links with --symbolic. When creating
hard links, each TARGET must exist. Symbolic links can hold arbitrary
text; if later resolved, a relative link is interpreted in relation to
its parent directory.

---

The only case that a link named '/usr/local/bin' is created is when the directory '/usr/local/bin' does not exists. If it exists, ln will create the link in the directory.

I suggest to insist in the documentation that the directory must exist.

Or we can add the command mkdir before the command ln like 'mkdir -p /usr/local/bin ; ln ...', but I think its not django related things (this directory should be create by the system admin, and not by the django user).

[Claude Paroz]

Or use the 4th form: ln -s -t /usr/local/bin WORKING-DIR/django-trunk/django/bin/django-admin.py?

[noria]

Yes, this command test that the -t parameter is an existing directory, so it seems to be a better solution.

[noria]

The (very hard) patch :)

[Claude Paroz]

In [17855]:

(The changeset message doesn't reference this ticket)

[Claude Paroz]

It appears that the -t option is not standard (​http://pubs.opengroup.org/onlinepubs/009695399/utilities/ln.html). It might be Linux-specific, at least not available on OSX. Will use the trailing slash solution instead.

[Claude Paroz]

In [17859]:

Fixed #17983 -- Re-fixed the ln syntax by adding a trailing slash to the destination directory.

The -t argument is not a POSIX standard. Thanks Aymeric Augustin for pointing the problem.