[TUHS] nl section delimiters

[TUHS] nl section delimiters

[Douglas McIlroy]

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> But it misses the coolness of the empty true(1).

Too cool. With an empty true(1), execl("true", "true", 0) is out in the
cold.

Doug

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[TUHS] Re: nl section delimiters

[Steffen Nurpmeso]

Douglas McIlroy wrote in
 <CAKH6PiWG-cFwQYPKDhKg_LdDKChC8odbxnnTOjC9+KZea7OgQA@mail.gmail.com>:
 |> But it misses the coolness of the empty true(1).
 |
 |Too cool. With an empty true(1), execl("true", "true", 0) is out in the
 |cold.

There i stand singing "ein Männlein steht im Walde" (a "little
man" stands in the forest).

..ok, but then i do note here and now the certain lists where the
question on whether an additional entry in the search path does
make any sense at all for certain constructs comes up regulary,
(even) i have lived this multiple times already, it is about

  The [.] command search [.] allows for a standard utility to be
  implemented as a regular built-in as long as it is found in the
  appropriate place in a PATH search.
  [.]command -v true might yield /bin/true or some similar pathname.

  Other [non-standard] utilities [.] might exist only as built-ins
  and have no pathname associated with them. These produce output
  identified as (regular) built-ins. Applications encountering
  these are not able to count on execing them, using them with
  nohup, overriding them with a different PATH, and so on.

The next POSIX standard will have around 4058 pages (3950 without
index) and 137171 lines (not counting index).

And i was surely laughing when this list it surely was came along
this somewhen in the past, and isn't that just "a muscle car":

  #?0|kent:unix-hist$ git show Research-V7:bin/true | wc -c
  0

Many greetings and best wishes!!

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)

[TUHS] Re: nl section delimiters

[Chet Ramey]

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On 5/11/24 4:48 PM, Steffen Nurpmeso wrote:

>    The [.] command search [.] allows for a standard utility to be
>    implemented as a regular built-in as long as it is found in the
>    appropriate place in a PATH search.
>    [.]command -v true might yield /bin/true or some similar pathname.

To be fair, no one really implements this. ksh93 is the shell that comes
closest.

The next edition of the standard acknowledges the status quo with the
`intrinsics' concept.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
		 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/


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[TUHS] nl section delimiters

[David Arnold]

nl(1) uses the notable character sequences “\:\:\:”, “\:\:”, and “\:” to delimit header, body, and trailer sections within its input. 

I wondered if anyone was able to shed light on the reason those were adopted as the defaults?

I would have expected perhaps something compatible with *roff (like, .\” something). 

FreeBSD claims nl first appeared in System III (although it previously claimed SVR2), but I haven’t dug into the implementation any further. 

Thanks in advance,



d