How to create link to directory in makefile in Linux?

Question

I have makefile containing code below.

ddd :
    @mkdir -p /full/path_new/to/new_dir
    @ln -fs /full/path_old/to/old_dir/private /full/path_new/to/new_dir/private

Linux ln command creates link in both directory taget and parent. It means I have:

/full/path_new/to/new_dir:
private -> /full/path_old/to/old_dir/private

but also old one gets link

/full/path_old/to/old_dir/private
private -> /full/path_old/to/old_dir/private

It cause I have something like

/full/path_old/to/old_dir/private/private/private/private (...) endless

How should I use ln command to have link in new_dir only?

As an aside, putting `@` on everything you do is insane. Run with `make -s` or specify `.SILENT: ddd` instead. — tripleee, Jun 12 '15 at 15:05

score 1 · Answer 1 · answered Jun 12 '15 at 14:54

1

You need to remove the existing link before you create it:

ddd :
        @mkdir -p /full/path_new/to/new_dir
        @rm -f /full/path_new/to/new_dir/private
        @ln -fs /full/path_old/to/old_dir/private /full/path_new/to/new_dir/private

answered Jun 12 '15 at 14:54

MadScientist

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score 0 · Answer 2 · answered Jun 12 '15 at 15:10

0

Assuming a clean slate, the proper way to do this would be to create a target which knows which dependency it is creating, and avoid creating it if it alread exists.

ddd: /full/path_new/to/new_dir/private
/full/path_new/to/new_dir/private:
    mkdir -p /full/path_new/to/new_dir
    ln -s /full/path/to/old_dir/private /full/path_new/to/new_dir

answered Jun 12 '15 at 15:10

tripleee

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You should still delete first, or use `-f`. If the symlink exists but points to an invalid directory then make will think it doesn't exist and run the `ln`, which will fail. – MadScientist Jun 12 '15 at 16:56
Although maybe it *should* fail in that case? – tripleee Jun 12 '15 at 19:37
Possibly, of course, but I'm hard-pressed to imagine a scenario where failure would be preferred. – MadScientist Jun 12 '15 at 19:56

How to create link to directory in makefile in Linux?

2 Answers2