eee-dee anyone?

[Lowell Gilbert]

Polytropon <freebsd at edvax.de> writes:

> On Sat, 30 Mar 2019 10:56:40 -0400, Lowell Gilbert wrote:
>> Because it's described by POSIX, ed(1) is with us to stay. Because it
>> has non-trivial differences between POSIX and BSD versions (which have
>> bitten me in the past), I use sed(1) regardless of whether ed would have
>> done the job. I suspect that is a common pattern.
>
> I think the aspect of POSIX-compliance is one of the main reasons
> that so many "old-fashioned" programs still exist in default
> installs of many UNIXes. UNIX books which cover UNIX in general,
> instead of concentrating on one specific Linux version, still
> often cover those "legacy tools". Yes, I just checked two:

ed(1) is particularly noteworthy here, because the BSD usages were
sufficiently engrained in system management practices (probably on
SunOS and Solaris machines at the time) that the POSIX spec actually
documents the BSD behaviour, even though it refers to the
non-BSD behaviour as "POSIX." This isn't the case for most other
utilities: various implementations often support lots and lots of
extensions that other implementations don't, but POSIX only covers
the common subset that's really portable.