== _head_ versus _sed_

I was recently reading [[More shell, less egg
http://www.leancrew.com/all-this/2011/12/more-shell-less-egg/]] and
ran across this:

> (I can't help wondering, though, why [Doug McIlroy] didn't use _head
> -${1}_ in the last line. It seems more natural than _sed_. Is it
> possible that _head_ hadn't been written yet?)

While _head_ postdates _sed_, this is probably not it. There is an old
Unix bias against using _head_ to the point that a lot of old Unix
people make a point of avoiding it in favour of _sed_.

This isn't a technical issue as much as a cultural issue. _head_ was
introduced in 4BSD, and there has always been a reaction against
4BSD that saw it as the point where the core Unix philosophy
started being lost. The introduction of a documented command
that could as well be a shell script (the [[original version
http://minnie.tuhs.org/cgi-bin/utree.pl?file=4BSD/usr/man/man1/head.1]]
only limited things by line) was often seen as yet another example of
BSD not really getting the point of things.  To put it one way, Unix was
not about having a system command for everything; it was about a kind of
near-mathematical minimalism.  Given _sed_, the basic 4BSD version of
_head_ is not minimal at all.

(_tail_ was different because you can't duplicate it with _sed_ or
anything else feasible; it did a unique job. I suspect that this is part
of why _tail_ appears in V7.)

I'm not quite old enough in my Unix exposure to have been part of this
first hand, but I was apparently exposed to enough old Unix hands at a
sensitive age to have picked this up as a reflexive habit. To this day,
I use '_sed Nq_' instead of _head_. It just feels (more) right.

=== Sidebar: would McIlroy have had _head_ available?

The short version is 'probably not'. The bit that's being quoted
is from 1986, well after 4BSD introduced _head_, but McIlroy was
at Bell Labs and was almost certainly using [[Research Unix
http://en.wikipedia.org/wiki/Research_Unix]]. While the version of
Research Unix from that era used a kernel derived from 4BSD, my
impression is that most of the userland programs were basically V7 and
I would be somewhat surprised if the Bell Labs people had picked up
_head_.