Re: [PATCH v2] ln: add the --relative option

[Pádraig Brady]

On 02/24/2012 12:12 AM, Pádraig Brady wrote:
> On 02/23/2012 09:28 PM, Eric Blake wrote:
>> On 02/23/2012 12:50 PM, address@hidden wrote:
>>> From: Harald Hoyer <address@hidden>
>>>
>>> With the "--relative --symbolic" options, ln computes the relative
>>> symbolic link for the user.
>>>
>>> So, ln works just as cp, but creates relative symbolic links instead
>>> of copying the file.
>>
>> In general, I like the idea.  I will point out that we now have realpath
>> that also can compute relative locations to an arbitrary starting point,
>> so we probably ought to share the code between the two programs rather
>> than rewriting it.
> 
> I like the functionality too.
> As Eric points out, the new `realpath` util has the
> relative path generation logic in it, which should be reused.
> To demonstrate the equivalence you could implement this
> functionality modulo option handling using `realpath` like:
> 
> ln--relative() {
>   target="$1"; link_name="$2"
>   rtarget="$(realpath -m "$target" --relative-to "$(dirname "$link_name")")"
>   ln -s -v "$rtarget" "$link_name"
> }
> 
> Now given the simplicity of the above, there is the argument
> that new options within ln are not needed. We've discussed
> on and off the idea of a contrib/ folder in coreutils to
> provide generally useful but higher level commands like this.
> Worth considering at least.

Attached is a quick PoC refactoring to use existing code.

cheers,
Pádraig.

ln-relative-refactor.diff
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