Re: Adding FAQ entry: shell built-in (echo/printf/etc.)

[Eric Blake]

On 08/11/2015 11:51 AM, Assaf Gordon wrote:
> Hello,
> 
> What do you think about adding a FAQ entry about confusing shell builtin
> with coreutils' programs?
> 

> shell builtin functions on do not support --version:
> 
>     $ echo --version
>     --version
>     $ printf --version
>     bash: printf: --: invalid option
>     printf: usage: printf [-v var] format [arguments]

Not true for ksh where builtins DO support --help/--version.  Also, a
future version of bash may follow suit from current ksh behavior:

$ ksh -c 'printf --version'
  version         printf (AT&T Research) 2009-02-02

[Note that ksh 'echo --version' outputs '--version', as POSIX does not
allow for extensions on that command; but presumably if bash adds
support for --help to its builtins, it will follow suit of coreutils in
having POSIXLY_CORRECT affect 'echo --version' behavior]

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

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