Re: Possible bug with grep/sed/tail?

[Jim Meyering]

Paolo Bonzini <address@hidden> wrote:
>> So -ol (that's an el) would mean line-buffered stdout?
>> That has to be equivalent to -o -l, and unless you consider
>> ordering and multiple -l options (e.g., "-i -l -o -l" is ugly),
>> then it doesn't let you line-buffer more than one of the three streams.
>
> It would be "+i::o::e::" in getopt parlance; no argument = no buffering,
> argument is "l" = line buffering, argument is numberic = given-size buffer.

Hi Paulo,

When designing new interfaces/tools, it's best to avoid that type of
optional argument.  This is partly a user interface consistency issue
(users are used to -il being equivalent to -i -l), and partly that it's
nonstandard: using "::" like that is a GNU getopt extension.