From: Pádraig Brady <P@draigBrady.com>
Date: Fri, 24 Jul 2009 23:46:12 +0000 (+0100)
Subject: doc: add a sort by line length example
X-Git-Tag: v7.5~51
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=2f4188ebec8a5cd833dc8061b714145a58dc86aa;p=thirdparty%2Fcoreutils.git

doc: add a sort by line length example

* doc/coreutils.texi (sort invocation): Add an example showing how
to sort data not directly supported by the sort command.
---

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 334d932de1..a804adb5b9 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -4257,6 +4257,17 @@ by the sort operation.
 @c printf 'c\n\nb\n\na\n'|perl -0pe 's/\n\n/\n\0/g'|sort -z|perl -0pe 's/\0/\n/g'
 @c @end example
 
+@item
+Use the common @acronym{DSU, Decorate Sort Undecorate} idiom to
+sort lines according to their length.
+
+@example
+awk '@{print length, $0@}' /etc/passwd | sort -n | cut -f2- -d' '
+@end example
+
+In general this technique can be used to sort data that the @command{sort}
+command does not support, or is inefficient at, sorting directly.
+
 @item
 Shuffle a list of directories, but preserve the order of files within
 each directory.  For instance, one could use this to generate a music