GNU bug report logs - #69807
questioning automatic -i in multicolumn pr

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Douglas McIlroy <douglas.mcilroy <at> dartmouth.edu>
To: bug-coreutils <at> gnu.org
Subject: questioning automatic -i in multicolumn pr
Date: Thu, 14 Mar 2024 16:31:34 -0400

[Message part 1 (text/plain, inline)]

Multicolumn options in pr imply option -i (tabification). The introduction
of tabs with physical rather than logical meaning makes output that is OK
for viewing only if you have correct tab stops, and is complicated for
further processing.  It caters for obsolete equipment--typewriters, on
which tabbing was appreciably faster than spacing.

As a wish-list item I propose abolishing implicit tabification. A second
choice (that doesn't buck Posix) is to provide an option to suppress
implicit tabification. At a bare minimum, document a workaround for the
inconvenient tabs, e.g. post-processing with pr -t -e.

[Message part 2 (text/html, inline)]

Message #10 received at 69807-done <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Douglas McIlroy <douglas.mcilroy <at> dartmouth.edu>, 69807-done <at> debbugs.gnu.org
Subject: Re: bug#69807: questioning automatic -i in multicolumn pr
Date: Thu, 21 Mar 2024 15:33:19 +0000

On 14/03/2024 20:31, Douglas McIlroy wrote:
> Multicolumn options in pr imply option -i (tabification). The introduction
> of tabs with physical rather than logical meaning makes output that is OK
> for viewing only if you have correct tab stops, and is complicated for
> further processing.  It caters for obsolete equipment--typewriters, on
> which tabbing was appreciably faster than spacing.
> 
> As a wish-list item I propose abolishing implicit tabification. A second
> choice (that doesn't buck Posix) is to provide an option to suppress
> implicit tabification. At a bare minimum, document a workaround for the
> inconvenient tabs, e.g. post-processing with pr -t -e.

Good call on the documentation.  I'll add this now:

commit 91e69cd2d02f015fc296e02388e0b18a293faa56 (HEAD -> master)
Author: Pádraig Brady <P <at> draigBrady.com>
Date:   Thu Mar 21 15:26:48 2024 +0000

    doc: pr: give solution to expanding TABs in multicolumn output

    * doc/coreutils.texi (pr invocation): Explicitly state that
    multicolumn output will convert spaces to TABs, and show that
    this can be undone with the `pr -t -e` or `expand` commands.
    Suggested by Douglas McIlroy in https://bugs.gnu.org/69807

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index e36269588..37d729089 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -2636,9 +2636,11 @@ This option might well cause some lines to be truncated.>
 lines in the columns on each page are balanced.  The options @option{-e}
 and @option{-i} are on for multiple text-column output.  Together with
 @option{-J} option column alignment and line truncation is turned off.
+Since spaces are converted to TABs in multicolumn output, they can be converted
+back by further processing through @command{pr -t -e} or @command{expand}.


thanks,
Pádraig

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