Re: What does an "export" do?

From: Dan Mercer (dmercer_at_mn.rr.com)
Date: 01/26/05 

Date: Wed, 26 Jan 2005 14:52:19 GMT

"Barry Margolin" <barmar@alum.mit.edu> wrote in message news:barmar-5CB325.01142626012005@comcast.dca.giganews.com...
: In article <kjsJd.225201$ye4.140349@twister.rdc-kc.rr.com>,
: "Dan Mercer" <dmercer@mn.rr.com> wrote:
:
: > "Kevin Rodgers" <ihs_4664@yahoo.com> wrote in message
: > news:35lig4F4q8ossU2@individual.net...
: > : Dan Mercer wrote:
: > : > "PM" <pm@gmx.de> wrote in message news:35l3vlF4osk4nU1@individual.net...
: > : > : Prab_kar@hotmail.com wrote:
: > : > : > In general, why do I need to export a variable?
: > : > To get it in called processes envp stack.
: > :
: > : In what way is envp a stack?
: >
: > The arguments and the environment are stacked in the same contiguous
: > space. Too many env vars and you may have no room to pass args.
: > Older versions of the Bourne shell also stored function definitions
: > in the environment space, so if you had a sufficiently large number
: > defined you also had trouble passing args.
:
: You seem to be using "stack" in a way different from most programmers.
: A stack is a data structure that allows you to add items at one end, and
: then retrieve them in the reverse order that they were added. The term
: is an analogy for the stack of plates in a buffet restaurant, where the
: staff adds new plates to the top and then customers take them off.
:

It's a hangover from learning UNIX on an Amdahl UTS system running under
IBM's VM/CMS. Using a 3270 terminal, no less. 3270's got a screen at
a time and the screen blinked with every transmission. So, since stderr
flushes after every byte you'd see:

    $ ls *
    $ls *
    l
BLINK
    $ls *
    ls
BLINK
    $ls *
    ls:
BLINK
     $ls *
    ls:
BLINK
     $ls *
    ls: *
BLINK

Well, you get the picture. You rapidly learned to do many things differently.

Anyways, the documentation borrowed terms from IBM mainframe
terminology, and, living fossil that I am, I never changed. Sometimes
I feel like a Coelacanth.

Dan Mercer

: --
: Barry Margolin, barmar@alum.mit.edu
: Arlington, MA
: *** PLEASE post questions in newsgroups, not directly to me ***

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