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bug#13301: patch to preserve field order in cut
From: |
Brad Cater |
Subject: |
bug#13301: patch to preserve field order in cut |
Date: |
Fri, 28 Dec 2012 17:19:32 -0500 |
Hello
I found that
echo "a,b,c" | cut -d"," -f1,2
gives the same result as
echo "a,b,c" | cut -d"," -f2,1
This means that it's necessary to use another process to re-order columns.
I have written a patch for cut.c included in coreutils-8.20 (
http://ftp.gnu.org/gnu/coreutils/coreutils-8.20.tar.xz) that adds a -p
option to preserve field order. This means that doing
echo "a,b,c" | cut -d"," -f2,1
still gives
a,b
but
echo "a,b,c" | cut -d"," -f2,1 -p
gives
b,a
The current implementation of cut.c uses putchar so that a full line need
not be held in memory, whereas holding a full line is required to re-order
the fields rather than printing them from an input stream. This patch uses
putchar when -p is not used, but it buffers a full line when -p is used.
What should I do next? I would like to have someone more experienced than I
evaluate the changes so that I can improve them and add this functionality
to coreutils.
Thank you
-Brad
cut.8.20.preserve_field_order.patch
Description: Binary data
- bug#13301: patch to preserve field order in cut,
Brad Cater <=