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Re: The First Pure Shell Contest (PUSH): relativepath

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In comp.unix.programmer Stephane CHAZELAS <stephane_chazelas@yahoo.fr> wrote:
# 2011-08-19, 17:23(+00), Jens Schweikhardt:
# [...]
#> The goal is to show the
#> absurdity of forking and nonportable constructs when a nice and small
#> pure shell solution solves the problem just as well.
# 
# What do you mean? The shell is is a command interpreter, it's
# whole raison d'etre is to run commands.

But commands can be built-in or external. External commands are forked
and potentially much slower than an equivalent built-in. Was the
"Motivation" paragraph that hard to understand?

# Awk and Perl are built in my POSIX shell and not "[". Which am I
# allowed to use?

Then our understanding of the term "built-in" is very different and
I'm afraid it is yours that is the non-conventional one.

#> Write a POSIX shell function named 'relativepath' which takes as
#> arguments two absolute canonicalized pathnames, and stores the relative
#> path from the first to the second in the variable "result" or "." when
#> the arguments are the same. Example: relativepath /foo/bar /foo/baz sets
#> result to "../baz".
# 
# You mean /foo/bar/../baz is meant to be /foo/baz? On my system,
# it's /usr/local/baz as /foo/bar is a symlink to /usr/local/bin.

No. I mean what my definition of "canonical" said.

#> A canonicalized pathname is one that contains no "."
#> or ".." directories and no occurrences of "//"; only the root directory
#> may end with "/".
# 
# You probably want to add as requirement that none of the
# components of either path should be a symbolic link.

The relative path is purely textual. The names don't even have to exist
in the file system. Maybe I should have added that to the task
description.

Regards,

	Jens
-- 
Jens Schweikhardt http://www.schweikhardt.net/
SIGSIG -- signature too long (core dumped)

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Thread

The First Pure Shell Contest (PUSH): relativepath Jens Schweikhardt <schweikh@schweikhardt.net> - 2011-08-19 17:23 +0000
  Re: The First Pure Shell Contest (PUSH): relativepath Stephane CHAZELAS <stephane_chazelas@yahoo.fr> - 2011-08-19 18:13 +0000
    Re: The First Pure Shell Contest (PUSH): relativepath Jens Schweikhardt <usenet@schweikhardt.net> - 2011-08-19 19:12 +0000
      Re: The First Pure Shell Contest (PUSH): relativepath pk <pk@pk.invalid> - 2011-08-19 21:14 +0200
        Re: The First Pure Shell Contest (PUSH): relativepath Jens Schweikhardt <usenet@schweikhardt.net> - 2011-08-19 19:29 +0000
          Re: The First Pure Shell Contest (PUSH): relativepath pk <pk@pk.invalid> - 2011-08-19 21:37 +0200
            Re: The First Pure Shell Contest (PUSH): relativepath Jens Schweikhardt <usenet@schweikhardt.net> - 2011-08-19 20:04 +0000
              Re: The First Pure Shell Contest (PUSH): relativepath pk <pk@pk.invalid> - 2011-08-19 22:25 +0200
                Re: The First Pure Shell Contest (PUSH): relativepath Jens Schweikhardt <usenet@schweikhardt.net> - 2011-08-19 21:08 +0000
  Re: The First Pure Shell Contest (PUSH): relativepath Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-19 19:58 +0100
    Re: The First Pure Shell Contest (PUSH): relativepath Jens Schweikhardt <usenet@schweikhardt.net> - 2011-08-19 19:23 +0000
      Re: The First Pure Shell Contest (PUSH): relativepath Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-19 22:18 +0100
  Re: The First Pure Shell Contest (PUSH): relativepath Stephane CHAZELAS <Stephane.CHAZELAS@free.fr> - 2011-08-20 20:07 +0000
    Re: The First Pure Shell Contest (PUSH): relativepath Jens Schweikhardt <usenet@schweikhardt.net> - 2011-08-21 10:43 +0000
    Re: The First Pure Shell Contest (PUSH): relativepath Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-21 15:14 +0100
      Re: The First Pure Shell Contest (PUSH): relativepath Janis Papanagnou <janis_papanagnou@hotmail.com> - 2011-08-21 18:28 +0300
      Re: The First Pure Shell Contest (PUSH): relativepath Stephane CHAZELAS <stephane_chazelas@yahoo.fr> - 2011-08-21 16:19 +0000
        Re: The First Pure Shell Contest (PUSH): relativepath Stephane CHAZELAS <stephane_chazelas@yahoo.fr> - 2011-08-21 20:12 +0000
  Re: The First Pure Shell Contest (PUSH): relativepath Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-22 21:15 +0100
    Re: The First Pure Shell Contest (PUSH): relativepath Stephane CHAZELAS <stephane_chazelas@yahoo.fr> - 2011-08-23 18:23 +0000
      Re: The First Pure Shell Contest (PUSH): relativepath Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-23 19:52 +0100
        Re: The First Pure Shell Contest (PUSH): relativepath Stephane CHAZELAS <stephane_chazelas@yahoo.fr> - 2011-08-23 21:56 +0000

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