Re: [Help-bash] Where is the usage of '.' in printf documented?

[Eric Blake]

On 03/20/2015 06:15 AM, Greg Wooledge wrote:
> On Thu, Mar 19, 2015 at 03:56:43PM -0500, Peng Yu wrote:
>> printf "%0.s-" {1..10}
> 
> I hate ugly hacks like this.  Truly, I do.

Concur.

> 
> What that bit of code says, in human-readable form, is "For every argument
> after the format, I want you to print the argument truncated to length
> zero, and then a hyphen."  Or in simpler terms, "print this many hyphens
> in a row in a really twisted way".

Rather, "For every argument after the format, I want you to print
0-padded strings truncated to length zero, and then a hyphen", except
that 0-padded strings are not defined by the C standard.

> 
> For some reason, the code you found has replaced the slightly more
> readable %0.0s with %0.s (and you could also use %.s for the same result,
> dropping both zeroes).  I'd at least stick with %0.0s because I find
> that the least unclear of the various forms.

I wouldn't.  %0.0s is undefined, while the shorter %.0s and %.s are
well-defined (even if arcane).

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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